The objective of this study was to test the effectiveness of recycled alum sludge, a low-cost mat... more The objective of this study was to test the effectiveness of recycled alum sludge, a low-cost material obtained after the coagulation/flocculation process, used as adsorbent to remove an anion dye called Melioderm black AFP 135 (MB-AFP 135) from Rouiba tannery dyeing wastewater (ACED Rouiba). Both of alum sludge and Melioderm black AFP 135 dye were characterized using different analysis methods. The experimental study, carried out in batch, made it possible to study the influence of the operating parameters such as pH solution, alum sludge dosage (C s), initial dye concentration (C 0) and temperature (T). The results showed that maximal MB-AFP 135 removal of 97% is obtained with: pH = 2, C s = 2 g/L, C 0 = 100 mg MB-AFP 135 L-1 and T = 20°C ± 1°C. The application of different adsorption models showed that the MB-AFP 135 adsorption on alum sludge is well described by Freundlich's and Langmuir's model. The maximum adsorption capacity is estimated at 123.46 mg/g.The data are well correlated with pseudo-second-order kinetic model and MB-AFP 135 adsorption is spontaneous (ΔG° < 0) and endothermic (ΔH° > 0). These experimental results have shown that reusing the alum sludge as a low-cost adsorbent can be considered as a reasonable alternative for such wastewater industry.
Leachate from municipalities' landfills represents a potential health risk to both surrounding ec... more Leachate from municipalities' landfills represents a potential health risk to both surrounding ecosystems and human populations. This study deals with the Ouled Fayet site (west of Algiers), which has been operational for five years, receiving non-hazardous, municipal and assimilated wastes from 34 municipalities corresponding to 363,000 T/year, stored in a settler and then rejected in the receiving environment. The composition of the wastes is extremely changeable according to the nature, the deposit time, and the climatic changes. Several landfill leachate samples were taken from the entry and exit settler, and evaluated. The analysis yielded the following results; very concentrated organic matter, chemical oxygen demand (COD) = 3552 mg/L, BOD 5 = 980 mg/L and BOD/COD ratio of 0.25. We observed that the water leachate is in the anaerobic reactions corresponding to the beginning of methane step, the pH of 8.27 reflects this biochemical evolution phase. Management of Algiers is undergoing drastic changes (source separation, closure of old landfills, reduction of the number etc.) that is why the municipalities are actually forced by the legislation to follow a minimization of the solid wastes by adopting a new strategy of reuse and recycling before all elimination or treatment possibility.
In this study, the sorption ability of nitrate containing MgAl layered double hydroxide as an ani... more In this study, the sorption ability of nitrate containing MgAl layered double hydroxide as an anion-exchanger to remove phosphate from a real effluent was investigated. The LDH material was prepared via coprecipitation method and characterized by X-ray diffraction, SEM, Fourier Transform Infrared, BET surface area, and pH zpc. The effect of physico-chemical key parameters on phosphate removal, such as sorbent dosage, solution pH, initial concentration, and contact time, has been studied in batch mode. The sorption reached equilibrium within 30 min. Furthermore, the sorption mechanism of phosphate onto MgAl-NO 3 LDH is a combination of both anion-exchange and electrostatic attraction. The equilibrium 8 data were tested using Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The results show that the Langmuir isotherm describes sufficiently the sorption equilibrium, offering a maximum sorption capacity of 64.10 mg/g. Sorption kinetic follows accurately pseudo-secondorder reaction. The sorbent reusability shows that regenerated LDH can be reused in subsequent sorption-regeneration cycles with a slight decrease in sorption capacity.
In this study, the sorption ability of MgAl-NO3 layered double hydroxide prepared by coprecipitat... more In this study, the sorption ability of MgAl-NO3 layered double hydroxide prepared by coprecipitation method to remove Cr(VI) from aqueous solution was investigated in fixed-bed column. The sorbent was characterized by XRD, SEM, FTIR, BET surface area, and pHzpc. The effects of bed height (2–5 cm), flow rate (5–20 mL/min), inlet Cr(VI) concentration (30–100 mg/L), and solution pH (3–8) on the breakthrough characteristics of the column were determined, and the optimum conditions were observed at 3.5 cm, 10 mL/min, 50 mg/L, and a pH of 6. Moreover, the performance of the sorbent to remove Cr(VI) from wastewater was also examined at optimum conditions. The results show high removal and good selectivity for Cr(VI) in wastewater containing large amounts of coexisting anions.
International Journal of Chemical Reactor Engineering, 2008
Effective removal of heavy metals from wastewater is one of the most important environmental chal... more Effective removal of heavy metals from wastewater is one of the most important environmental challenges facing the world. Various techniques are used to remove the metals. Biosorption has gained credibility in the last decade because of its good performance and low cost. The objective of this study is to explore the use of olive pits for cadmium wastewater removal. The effects of mixing rate, pH, particle size, biomass and initial concentration and equilibrium metal ion concentration are evaluated. Results indicate nearly linear uptake by the biomass with increasing initial cadmium concentration. Adsorption increases rapidly in the pH range of 3-9, then levels off. Cadmium concentration uptake increase with increasing biomass concentration until reaching 5 g/L. Mixing rates up to 250 rpm increase uptake, however, higher mixing rates result in a vortex that incorporated air into the mixture, this resulted in a decrease in uptake. The adsorption isotherm appears to follow the Langmuir...
In this study, adsorption capacities of untreated Alfa stems were tested for the removal of methy... more In this study, adsorption capacities of untreated Alfa stems were tested for the removal of methylene blue (MB) as a dye in aqueous solutions. The effects of initial dye concentration (10-150 mg/L), contact time, adsorbent dose (0.25-12.5 g/L), solution pH (2-12), temperature (283-330 K) and ionic strength (5-100 mg/L) on MB adsorption were investigated. The thermodynamic parameters, the kinetics and the factors controlling the adsorption process were also calculated and discussed. The experimental data modelling showed that the models of Langmuir and pseudo-second order, describe perfectly the adsorption process. The maximum value of the adsorption capacity calculated according to the Langmuir model is 200 mg/g. The thermodynamic parameters showed that MB adsorption onto Alfa grass is a favourable endothermic and spontaneous phenomenon and confirms the Alfa grass affinity for MB. The Alfa stems in a rough state have good adsorption effectiveness with respect to dyes without a preliminary treatment. In addition, the availability and the low cost of the Alfa grass could lead to its use for the coloured wastewater treatment.
Wet granulation is a size enlargement operation which is widely used in pharmaceutical field to m... more Wet granulation is a size enlargement operation which is widely used in pharmaceutical field to modify the powder properties. In fact, the friability and hardness of the final solid dosage form (i.e., tablets), may be significantly improved if initial powders are prior granulated to the desired size and shape. In this optic, a parametric study was carried out with two excipients, microcrystalline cellulose and corn starch, two excipients generally used for tabletting but with poor flow characteristics. A laboratory scale mixer granulator Lodige of 4 litres capacity equipped with blades has been used to achieve mixing and wet granulation. The effect of some parameters such as excipients proportions, binder quantity, rotational speed blades, drying temperature, size aperture of screens and residual humidity were investigated. The morphology of obtained granules was visualized by optical microscope (OM) and scanning electron microscope (SEM). Experimental results showed that increasing...
The present paper concerns the valorization of a botanic solid waste to synthetize an activated c... more The present paper concerns the valorization of a botanic solid waste to synthetize an activated carbon from the cypress cones (Cupressus sempervirens cones) that grows spontaneously in the north region of Algeria. The goal and the novelty of this study is the feasibility of chemical activation with orthophosphoric acid of cypress cones as a new low-cost precursor. The performance of this activated carbon is tested in batch adsorption of the basic dye (methylene blue) from aqueous solutions. An experimental factorial design was used to determine the interaction effects of the operating conditions for both steps activation and carbonization. The maximum 97.29 % of dye elimination was obtained with the optimal activated carbon (AC) produced under the operating conditions, impregnation mass ratio of 1:1 for 5 hours and carbonization at 873 K for 4 hours. The effects of pH solution, initial dye concentration, mass adsorbent, and temperature on the adsorption of methylene blue on optimal ...
An investigation on the efficiency and compatibility of anaerobic co-digestion of three substrate... more An investigation on the efficiency and compatibility of anaerobic co-digestion of three substrates: food wastes (FW), chicken manure (CM) and digested sludge (DS) was carried out. Mixtures of two and three co-substrates in batch experiments were conducted in 0.5-L bioreactors during 8 days under mesophilic conditions. Parameters analysis such as pH, volatile fatty acids, free ammonia (NH3), total solids (TS) and total volatile solids (TVS) was used to explain the behavior of each substrate and their mixtures. For the anaerobic digestion of two co-substrates (CM/DS with 30/70 ratio), total biogas production was equal to 2.5 L and was greater than the volume obtained for the same ratio of FW with DS. The three co-substrates (FW/CM/DS) digestion with (20/10/70) ratio showed best performances for total volatile solids (TVS) reduction and process stability. On the pilot bioreactor, a ratio of (20/5/75) was used for (FW/CM/DS) anaerobic digestion. After 50 days retention time, the biogas production reached 413.85 L/g TVSadd with TS and TVS reduction of 79 and 87% respectively.
A new activated carbon from local cypress cones (CCAC) was prepared using phosphoric acid as a ch... more A new activated carbon from local cypress cones (CCAC) was prepared using phosphoric acid as a chemical activating agent. It presented a Brunauer, Emmett and Teller surface area (SBET) equal to 379.5117 ± 2.3509 m2 g−1 with an amorphous nature. Scanning electron microscopy analysis revealed a heterogeneous and random shape of pores. The reduction in colour and chemical oxygen demand (COD) from the industrial aqueous effluent from the textile company “COTITEX” was the principal performance study of the resulting material. The kinetic data of the adsorption process obeyed a pseudo-second-order model with R2 of 0.988. From five studied parameters, only the initial COD concentration, the pH and the temperature influenced the COD reduction at equilibrium. Maximum COD and colour removal, respectively, 19% and 80.4% were recorded under optimal adsorption conditions of 2 g L−1 of the adsorbent amount, 323°K of operating temperature, pH = 11 and a stirring speed = 300 rpm. The present study showed that CCAC could be a proper material for coloured effluent treatment, whereas, for a better COD reduction, pretreatment is required.
Soil and Sediment Contamination: An International Journal
ABSTRACT Oil industry generates a considerable amount of petroleum drill cuttings (PDC) which mus... more ABSTRACT Oil industry generates a considerable amount of petroleum drill cuttings (PDC) which must be managed and treated properly. The objective of this work is to develop a treatment method in order to reduce or eliminate the PDC pollution composed mainly of hydrocarbons. The stabilization/solidification (S/S) is combined with biological treatment and the Portland cement was used as a hydraulic binder; whereas, the cement quantity was partially substituted by two additives such as compost and bentonite. The experimental solidification tests were evaluated by the monitoring of the unconfined compressive strength (UCS) and the hydrocarbon degradation within the cementitious matrix (CM) by the measurement of total petroleum hydrocarbons (TPH). The results showed that after 28 days of cure, the UCS was significantly affected by additives’ incorporation in the solidification formulation (SF). In contrast, it favored the TPH degradation within the CM. The additives’ incorporation of 2%, 4% and 6% reduced the TPH content to 29.47%, 33.96% and 37.21% for bentonite and 53.17%, 61.51% and 64.43% for compost. For the additive mixture, a reduction of 59.62%, 65.35% and 72.53% was recorded.
In this study, the performance of a cypress cone-based activated carbon was tested for the COD re... more In this study, the performance of a cypress cone-based activated carbon was tested for the COD reduction from industrial textile wastewater. These cypress cones were locally collected after maturation. The Doehlert response surface design was used to simulate and optimize the decrease in COD in treated wastewater. The dominant parameters for COD removal in the effluent were the temperature, the amount of adsorbent and the pH of the initial solution. The obtained model fit the experimental results with high precision (R2 > 0.93) and low Fisher probability ( temperature > initial pH. Under the optimal conditions predicted by the regression, a maximum COD reduction could be obtained with a temperature of 319 K at pH 12 and an activated carbon concentration of 1.144 g L−1 after 1 h treatment. Meanwhile, the designed adsorbent realized the decrease in colour (80.4%), COD (19%) and turbidity (67.1%) of wastewater. It could be concluded that cypress cone-based activated carbon is promising in the treatment of textile wastewater. The increase in COD removal rate through hybridization of processes is being considered for future research.
Natural sand was the first material introduced as a proppant to hydraulic fracturing operations t... more Natural sand was the first material introduced as a proppant to hydraulic fracturing operations to keep induced rock fractures both open and conductive. It has remained the most commonly us...
ABSTRACT Incineration residues of expired medications (IREMs) were chemically treated (IREM-T) by... more ABSTRACT Incineration residues of expired medications (IREMs) were chemically treated (IREM-T) by a combination of mixed salts (CaCl2, MgCl2) and thermal treatments with NaOH. They were characterized and used for simultaneous ammonia and phosphates adsorption from wastewater. Batch experiments were carried out to investigate the effect of contact time, adsorbent dose, initial concentration, pH and temperature. The maximum adsorption capacity for phosphate and ammonium on IREM-T was found to be 24.68 and 34.30 mg g−1, respectively, at the same initial concentration of 50 mg L−1 on 5 g L−1 of IREM-T. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich adsorption models were applied to analyze the adsorption data. The equilibrium data fitted well with the Langmuir isotherm. To examine the adsorption mechanism, pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied to analyze the experimental data. All the linear correlation coefficients of the second-order model were found to be statistically significant, indicating the applicability of this kinetic equation to the adsorption of both phosphate and ammonium ions. This study revealed that IREM-T has the potential to be an efficient adsorbent for simultaneous nutrient removal. The effectiveness of this material was evaluated by applying this process to Algiers urban wastewater. GRAPHICAL ABSTRACT
This study describes the sorption of Cr(VI) by MgAl-NO3 hydrotalcite in a fixed-bed column. The s... more This study describes the sorption of Cr(VI) by MgAl-NO3 hydrotalcite in a fixed-bed column. The sorbent was prepared via coprecipitation method and characterized by XRD, FTIR, BET surface area and pHzpc. The effects of operating parameters such as bed height, flow rate and inlet concentration were investigated in continuous mode. As a result, the exhaustion time increased with the increase of bed height, decrease of flow rate and inlet concentration. A mathematical model based on the constant pattern theory and the Freundlich isotherm was applied to predict the experimental data, and to evaluate the model parameters of the fixed-bed column. The developed model describes well the breakthrough curves at various operating conditions. The calculated volumetric mass transfer coefficient KLa depends directly on these conditions. KLa increased with increasing flow rate and inlet concentration, while remained almost constant with varying bed height.
Abstract The influence of interlayer anions such as NO 3 − , SO 4 2 − and Cl − on Mg–Al hydrotalc... more Abstract The influence of interlayer anions such as NO 3 − , SO 4 2 − and Cl − on Mg–Al hydrotalcites for Cr(VI) removal from aqueous solution was studied. The structure of the prepared LDHs was characterized by XRD, SEM, FTIR, TGA, BET surface area and pH zpc . The sorbent ability and sorption mechanisms were also investigated. The LDHs exhibit high removal for Cr(VI), and the sorbed amount depends on the nature of interlayer anion, which decreased in the following order: NO 3 − > Cl − > SO 4 2 − . Nitrate-containing LDH reached a Cr(VI) sorption equilibrium within only 30 min. The effects of operating conditions, including initial concentration, solution pH, agitation time and sorbent amount have been studied in batch mode. The optimum conditions were observed at an initial concentration of 100 mg·L − 1 , pH = 6, agitation time of 60 min and a sorbent dose of 2 g·L − 1 . The equilibrium data were fitted to the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The Langmuir model was found to sufficiently describe the sorption process, offering a maximum sorption capacity of 71.91 mg·g − 1 . The sorption kinetic follows pseudo-second-order reaction with high accuracy. Thermodynamic parameters suggested that the sorption process is spontaneous and endothermic in nature.
Biological treatment has been carried out in two different systems: aerated closed and three-phas... more Biological treatment has been carried out in two different systems: aerated closed and three-phase fluidized bed reactors for hydrocarbons removal from refinery wastewaters. For the two systems, hydrodynamic study allowed the determination of operating conditions before treatment experiments. Then, in a second time, biological treatments have been conducted in the same operating conditions. The obtained results showed that in the three-phase fluidized bed we can degrade hydrocarbons more rapidly than in a closed aerated bioreactor. Among the different appropriate techniques available to create efficient contacts between phases, the three-phase fluidization G/L/S where carrier particles are moving inside the reactor seems very interesting. It allows an intimate contact between phases and present many advantages concerning hydrodynamic and mass transfer phenomena. In fact, depending on operating conditions and the bubble flow behaviour, the three-phase fluidized bed could display diff...
The batch removal of Basic Red 46 (BR 46) from aqueous solution using low-cost adsorbents, such a... more The batch removal of Basic Red 46 (BR 46) from aqueous solution using low-cost adsorbents, such as incineration residues (IR) of pharmaceutical wastes, under different experimental conditions was investigated in this study.
The objective of this study was to test the effectiveness of recycled alum sludge, a low-cost mat... more The objective of this study was to test the effectiveness of recycled alum sludge, a low-cost material obtained after the coagulation/flocculation process, used as adsorbent to remove an anion dye called Melioderm black AFP 135 (MB-AFP 135) from Rouiba tannery dyeing wastewater (ACED Rouiba). Both of alum sludge and Melioderm black AFP 135 dye were characterized using different analysis methods. The experimental study, carried out in batch, made it possible to study the influence of the operating parameters such as pH solution, alum sludge dosage (C s), initial dye concentration (C 0) and temperature (T). The results showed that maximal MB-AFP 135 removal of 97% is obtained with: pH = 2, C s = 2 g/L, C 0 = 100 mg MB-AFP 135 L-1 and T = 20°C ± 1°C. The application of different adsorption models showed that the MB-AFP 135 adsorption on alum sludge is well described by Freundlich's and Langmuir's model. The maximum adsorption capacity is estimated at 123.46 mg/g.The data are well correlated with pseudo-second-order kinetic model and MB-AFP 135 adsorption is spontaneous (ΔG° < 0) and endothermic (ΔH° > 0). These experimental results have shown that reusing the alum sludge as a low-cost adsorbent can be considered as a reasonable alternative for such wastewater industry.
Leachate from municipalities' landfills represents a potential health risk to both surrounding ec... more Leachate from municipalities' landfills represents a potential health risk to both surrounding ecosystems and human populations. This study deals with the Ouled Fayet site (west of Algiers), which has been operational for five years, receiving non-hazardous, municipal and assimilated wastes from 34 municipalities corresponding to 363,000 T/year, stored in a settler and then rejected in the receiving environment. The composition of the wastes is extremely changeable according to the nature, the deposit time, and the climatic changes. Several landfill leachate samples were taken from the entry and exit settler, and evaluated. The analysis yielded the following results; very concentrated organic matter, chemical oxygen demand (COD) = 3552 mg/L, BOD 5 = 980 mg/L and BOD/COD ratio of 0.25. We observed that the water leachate is in the anaerobic reactions corresponding to the beginning of methane step, the pH of 8.27 reflects this biochemical evolution phase. Management of Algiers is undergoing drastic changes (source separation, closure of old landfills, reduction of the number etc.) that is why the municipalities are actually forced by the legislation to follow a minimization of the solid wastes by adopting a new strategy of reuse and recycling before all elimination or treatment possibility.
In this study, the sorption ability of nitrate containing MgAl layered double hydroxide as an ani... more In this study, the sorption ability of nitrate containing MgAl layered double hydroxide as an anion-exchanger to remove phosphate from a real effluent was investigated. The LDH material was prepared via coprecipitation method and characterized by X-ray diffraction, SEM, Fourier Transform Infrared, BET surface area, and pH zpc. The effect of physico-chemical key parameters on phosphate removal, such as sorbent dosage, solution pH, initial concentration, and contact time, has been studied in batch mode. The sorption reached equilibrium within 30 min. Furthermore, the sorption mechanism of phosphate onto MgAl-NO 3 LDH is a combination of both anion-exchange and electrostatic attraction. The equilibrium 8 data were tested using Langmuir, Freundlich, and Dubinin-Radushkevich isotherms. The results show that the Langmuir isotherm describes sufficiently the sorption equilibrium, offering a maximum sorption capacity of 64.10 mg/g. Sorption kinetic follows accurately pseudo-secondorder reaction. The sorbent reusability shows that regenerated LDH can be reused in subsequent sorption-regeneration cycles with a slight decrease in sorption capacity.
In this study, the sorption ability of MgAl-NO3 layered double hydroxide prepared by coprecipitat... more In this study, the sorption ability of MgAl-NO3 layered double hydroxide prepared by coprecipitation method to remove Cr(VI) from aqueous solution was investigated in fixed-bed column. The sorbent was characterized by XRD, SEM, FTIR, BET surface area, and pHzpc. The effects of bed height (2–5 cm), flow rate (5–20 mL/min), inlet Cr(VI) concentration (30–100 mg/L), and solution pH (3–8) on the breakthrough characteristics of the column were determined, and the optimum conditions were observed at 3.5 cm, 10 mL/min, 50 mg/L, and a pH of 6. Moreover, the performance of the sorbent to remove Cr(VI) from wastewater was also examined at optimum conditions. The results show high removal and good selectivity for Cr(VI) in wastewater containing large amounts of coexisting anions.
International Journal of Chemical Reactor Engineering, 2008
Effective removal of heavy metals from wastewater is one of the most important environmental chal... more Effective removal of heavy metals from wastewater is one of the most important environmental challenges facing the world. Various techniques are used to remove the metals. Biosorption has gained credibility in the last decade because of its good performance and low cost. The objective of this study is to explore the use of olive pits for cadmium wastewater removal. The effects of mixing rate, pH, particle size, biomass and initial concentration and equilibrium metal ion concentration are evaluated. Results indicate nearly linear uptake by the biomass with increasing initial cadmium concentration. Adsorption increases rapidly in the pH range of 3-9, then levels off. Cadmium concentration uptake increase with increasing biomass concentration until reaching 5 g/L. Mixing rates up to 250 rpm increase uptake, however, higher mixing rates result in a vortex that incorporated air into the mixture, this resulted in a decrease in uptake. The adsorption isotherm appears to follow the Langmuir...
In this study, adsorption capacities of untreated Alfa stems were tested for the removal of methy... more In this study, adsorption capacities of untreated Alfa stems were tested for the removal of methylene blue (MB) as a dye in aqueous solutions. The effects of initial dye concentration (10-150 mg/L), contact time, adsorbent dose (0.25-12.5 g/L), solution pH (2-12), temperature (283-330 K) and ionic strength (5-100 mg/L) on MB adsorption were investigated. The thermodynamic parameters, the kinetics and the factors controlling the adsorption process were also calculated and discussed. The experimental data modelling showed that the models of Langmuir and pseudo-second order, describe perfectly the adsorption process. The maximum value of the adsorption capacity calculated according to the Langmuir model is 200 mg/g. The thermodynamic parameters showed that MB adsorption onto Alfa grass is a favourable endothermic and spontaneous phenomenon and confirms the Alfa grass affinity for MB. The Alfa stems in a rough state have good adsorption effectiveness with respect to dyes without a preliminary treatment. In addition, the availability and the low cost of the Alfa grass could lead to its use for the coloured wastewater treatment.
Wet granulation is a size enlargement operation which is widely used in pharmaceutical field to m... more Wet granulation is a size enlargement operation which is widely used in pharmaceutical field to modify the powder properties. In fact, the friability and hardness of the final solid dosage form (i.e., tablets), may be significantly improved if initial powders are prior granulated to the desired size and shape. In this optic, a parametric study was carried out with two excipients, microcrystalline cellulose and corn starch, two excipients generally used for tabletting but with poor flow characteristics. A laboratory scale mixer granulator Lodige of 4 litres capacity equipped with blades has been used to achieve mixing and wet granulation. The effect of some parameters such as excipients proportions, binder quantity, rotational speed blades, drying temperature, size aperture of screens and residual humidity were investigated. The morphology of obtained granules was visualized by optical microscope (OM) and scanning electron microscope (SEM). Experimental results showed that increasing...
The present paper concerns the valorization of a botanic solid waste to synthetize an activated c... more The present paper concerns the valorization of a botanic solid waste to synthetize an activated carbon from the cypress cones (Cupressus sempervirens cones) that grows spontaneously in the north region of Algeria. The goal and the novelty of this study is the feasibility of chemical activation with orthophosphoric acid of cypress cones as a new low-cost precursor. The performance of this activated carbon is tested in batch adsorption of the basic dye (methylene blue) from aqueous solutions. An experimental factorial design was used to determine the interaction effects of the operating conditions for both steps activation and carbonization. The maximum 97.29 % of dye elimination was obtained with the optimal activated carbon (AC) produced under the operating conditions, impregnation mass ratio of 1:1 for 5 hours and carbonization at 873 K for 4 hours. The effects of pH solution, initial dye concentration, mass adsorbent, and temperature on the adsorption of methylene blue on optimal ...
An investigation on the efficiency and compatibility of anaerobic co-digestion of three substrate... more An investigation on the efficiency and compatibility of anaerobic co-digestion of three substrates: food wastes (FW), chicken manure (CM) and digested sludge (DS) was carried out. Mixtures of two and three co-substrates in batch experiments were conducted in 0.5-L bioreactors during 8 days under mesophilic conditions. Parameters analysis such as pH, volatile fatty acids, free ammonia (NH3), total solids (TS) and total volatile solids (TVS) was used to explain the behavior of each substrate and their mixtures. For the anaerobic digestion of two co-substrates (CM/DS with 30/70 ratio), total biogas production was equal to 2.5 L and was greater than the volume obtained for the same ratio of FW with DS. The three co-substrates (FW/CM/DS) digestion with (20/10/70) ratio showed best performances for total volatile solids (TVS) reduction and process stability. On the pilot bioreactor, a ratio of (20/5/75) was used for (FW/CM/DS) anaerobic digestion. After 50 days retention time, the biogas production reached 413.85 L/g TVSadd with TS and TVS reduction of 79 and 87% respectively.
A new activated carbon from local cypress cones (CCAC) was prepared using phosphoric acid as a ch... more A new activated carbon from local cypress cones (CCAC) was prepared using phosphoric acid as a chemical activating agent. It presented a Brunauer, Emmett and Teller surface area (SBET) equal to 379.5117 ± 2.3509 m2 g−1 with an amorphous nature. Scanning electron microscopy analysis revealed a heterogeneous and random shape of pores. The reduction in colour and chemical oxygen demand (COD) from the industrial aqueous effluent from the textile company “COTITEX” was the principal performance study of the resulting material. The kinetic data of the adsorption process obeyed a pseudo-second-order model with R2 of 0.988. From five studied parameters, only the initial COD concentration, the pH and the temperature influenced the COD reduction at equilibrium. Maximum COD and colour removal, respectively, 19% and 80.4% were recorded under optimal adsorption conditions of 2 g L−1 of the adsorbent amount, 323°K of operating temperature, pH = 11 and a stirring speed = 300 rpm. The present study showed that CCAC could be a proper material for coloured effluent treatment, whereas, for a better COD reduction, pretreatment is required.
Soil and Sediment Contamination: An International Journal
ABSTRACT Oil industry generates a considerable amount of petroleum drill cuttings (PDC) which mus... more ABSTRACT Oil industry generates a considerable amount of petroleum drill cuttings (PDC) which must be managed and treated properly. The objective of this work is to develop a treatment method in order to reduce or eliminate the PDC pollution composed mainly of hydrocarbons. The stabilization/solidification (S/S) is combined with biological treatment and the Portland cement was used as a hydraulic binder; whereas, the cement quantity was partially substituted by two additives such as compost and bentonite. The experimental solidification tests were evaluated by the monitoring of the unconfined compressive strength (UCS) and the hydrocarbon degradation within the cementitious matrix (CM) by the measurement of total petroleum hydrocarbons (TPH). The results showed that after 28 days of cure, the UCS was significantly affected by additives’ incorporation in the solidification formulation (SF). In contrast, it favored the TPH degradation within the CM. The additives’ incorporation of 2%, 4% and 6% reduced the TPH content to 29.47%, 33.96% and 37.21% for bentonite and 53.17%, 61.51% and 64.43% for compost. For the additive mixture, a reduction of 59.62%, 65.35% and 72.53% was recorded.
In this study, the performance of a cypress cone-based activated carbon was tested for the COD re... more In this study, the performance of a cypress cone-based activated carbon was tested for the COD reduction from industrial textile wastewater. These cypress cones were locally collected after maturation. The Doehlert response surface design was used to simulate and optimize the decrease in COD in treated wastewater. The dominant parameters for COD removal in the effluent were the temperature, the amount of adsorbent and the pH of the initial solution. The obtained model fit the experimental results with high precision (R2 > 0.93) and low Fisher probability ( temperature > initial pH. Under the optimal conditions predicted by the regression, a maximum COD reduction could be obtained with a temperature of 319 K at pH 12 and an activated carbon concentration of 1.144 g L−1 after 1 h treatment. Meanwhile, the designed adsorbent realized the decrease in colour (80.4%), COD (19%) and turbidity (67.1%) of wastewater. It could be concluded that cypress cone-based activated carbon is promising in the treatment of textile wastewater. The increase in COD removal rate through hybridization of processes is being considered for future research.
Natural sand was the first material introduced as a proppant to hydraulic fracturing operations t... more Natural sand was the first material introduced as a proppant to hydraulic fracturing operations to keep induced rock fractures both open and conductive. It has remained the most commonly us...
ABSTRACT Incineration residues of expired medications (IREMs) were chemically treated (IREM-T) by... more ABSTRACT Incineration residues of expired medications (IREMs) were chemically treated (IREM-T) by a combination of mixed salts (CaCl2, MgCl2) and thermal treatments with NaOH. They were characterized and used for simultaneous ammonia and phosphates adsorption from wastewater. Batch experiments were carried out to investigate the effect of contact time, adsorbent dose, initial concentration, pH and temperature. The maximum adsorption capacity for phosphate and ammonium on IREM-T was found to be 24.68 and 34.30 mg g−1, respectively, at the same initial concentration of 50 mg L−1 on 5 g L−1 of IREM-T. Langmuir, Freundlich, Temkin and Dubinin–Radushkevich adsorption models were applied to analyze the adsorption data. The equilibrium data fitted well with the Langmuir isotherm. To examine the adsorption mechanism, pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied to analyze the experimental data. All the linear correlation coefficients of the second-order model were found to be statistically significant, indicating the applicability of this kinetic equation to the adsorption of both phosphate and ammonium ions. This study revealed that IREM-T has the potential to be an efficient adsorbent for simultaneous nutrient removal. The effectiveness of this material was evaluated by applying this process to Algiers urban wastewater. GRAPHICAL ABSTRACT
This study describes the sorption of Cr(VI) by MgAl-NO3 hydrotalcite in a fixed-bed column. The s... more This study describes the sorption of Cr(VI) by MgAl-NO3 hydrotalcite in a fixed-bed column. The sorbent was prepared via coprecipitation method and characterized by XRD, FTIR, BET surface area and pHzpc. The effects of operating parameters such as bed height, flow rate and inlet concentration were investigated in continuous mode. As a result, the exhaustion time increased with the increase of bed height, decrease of flow rate and inlet concentration. A mathematical model based on the constant pattern theory and the Freundlich isotherm was applied to predict the experimental data, and to evaluate the model parameters of the fixed-bed column. The developed model describes well the breakthrough curves at various operating conditions. The calculated volumetric mass transfer coefficient KLa depends directly on these conditions. KLa increased with increasing flow rate and inlet concentration, while remained almost constant with varying bed height.
Abstract The influence of interlayer anions such as NO 3 − , SO 4 2 − and Cl − on Mg–Al hydrotalc... more Abstract The influence of interlayer anions such as NO 3 − , SO 4 2 − and Cl − on Mg–Al hydrotalcites for Cr(VI) removal from aqueous solution was studied. The structure of the prepared LDHs was characterized by XRD, SEM, FTIR, TGA, BET surface area and pH zpc . The sorbent ability and sorption mechanisms were also investigated. The LDHs exhibit high removal for Cr(VI), and the sorbed amount depends on the nature of interlayer anion, which decreased in the following order: NO 3 − > Cl − > SO 4 2 − . Nitrate-containing LDH reached a Cr(VI) sorption equilibrium within only 30 min. The effects of operating conditions, including initial concentration, solution pH, agitation time and sorbent amount have been studied in batch mode. The optimum conditions were observed at an initial concentration of 100 mg·L − 1 , pH = 6, agitation time of 60 min and a sorbent dose of 2 g·L − 1 . The equilibrium data were fitted to the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The Langmuir model was found to sufficiently describe the sorption process, offering a maximum sorption capacity of 71.91 mg·g − 1 . The sorption kinetic follows pseudo-second-order reaction with high accuracy. Thermodynamic parameters suggested that the sorption process is spontaneous and endothermic in nature.
Biological treatment has been carried out in two different systems: aerated closed and three-phas... more Biological treatment has been carried out in two different systems: aerated closed and three-phase fluidized bed reactors for hydrocarbons removal from refinery wastewaters. For the two systems, hydrodynamic study allowed the determination of operating conditions before treatment experiments. Then, in a second time, biological treatments have been conducted in the same operating conditions. The obtained results showed that in the three-phase fluidized bed we can degrade hydrocarbons more rapidly than in a closed aerated bioreactor. Among the different appropriate techniques available to create efficient contacts between phases, the three-phase fluidization G/L/S where carrier particles are moving inside the reactor seems very interesting. It allows an intimate contact between phases and present many advantages concerning hydrodynamic and mass transfer phenomena. In fact, depending on operating conditions and the bubble flow behaviour, the three-phase fluidized bed could display diff...
The batch removal of Basic Red 46 (BR 46) from aqueous solution using low-cost adsorbents, such a... more The batch removal of Basic Red 46 (BR 46) from aqueous solution using low-cost adsorbents, such as incineration residues (IR) of pharmaceutical wastes, under different experimental conditions was investigated in this study.
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