Adsorption Of Chemical Oxygen Demand Research Articles

Lanthanum ferrite modified filling materials and its enhancement for phosphorus and COD removal: Performance and mechanism

Previous studies have developed numerous adsorption composite materials demonstrating substantial removal efficiencies for phosphorus (P) and chemical oxygen demand (COD). However, most of materials targeted single contaminant and were inconvenient to apply in real water bodies owing to size limitation. In the current study, three composite materials‑lanthanum ferrite-modified Quartz balls/Maifan stones/Honeycomb ceramics-were synthesized using one step co-precipitation method. Structural and morphological changes of pre- and post-adsorption were examined through Scanning Electron Microscope - Energy Dispersive Spectrometer (SEM-EDS) and X-ray diffraction (XRD). Kinetics, thermodynamics, and isotherm models were simulated for the analysis of P and COD adsorption. X-ray photoelectron spectroscopy (XPS) and Fourier-transform infrared spectroscopy (FTIR) were employed to elucidate the adsorption mechanisms. The results demonstrated that these materials achieved P maximal removal rate of 99.56 % and COD maximal removal rate up to 94.82 %. The second-order kinetic model for P adsorption was more excellent than that of the first-order model, and the intra-particle diffusion model more accurately described the COD adsorption. Both the Langmuir and Freundlich were used to fit the adsorption isotherm data for P and COD. XPS and FTIR revealed that the adsorption mechanisms for P were ligand exchange and chemical precipitation. Whereas the adsorption mechanisms for COD were ligand exchange and physical adsorption. The materials in the actual farmland drainage performed excellent and effectively reduced the concentration of P and COD up to 68.58 % and 53.98 %, respectively. The lanthanum ferrite-modified fillers provide accessible, universal and bifunctional option for controlling agricultural non-point source pollution.

A Laboratory Investigation of the Adsorption Performance and Mechanism of Organics in Industrial Wastewater on mp-Zr(OH)4

We reported on the development of mesoporous zirconium hydroxide (mp-Zr(OH)4) sorbents with high capacity for adsorptive removal of organic pollutants from industrial wastewater. The sorbent was prepared by a one-step chemical precipitation method at room temperature. The adsorption capacity and removal efficiency for the chemical oxygen demand (COD) of the industrial wastewater were studied using an automatic adsorption measurement apparatus. The effects of different parameters (adsorbent dosage, adsorption time, regeneration times, adsorbate's molecular weight and adsorbate solubility), isotherm, thermodynamics, and kinetics were evaluated. By analyzing scanning electron microscopy (SEM) images and powder X-ray diffractograms (XRD) no obvious differences were observed for the sorbents before and after the adsorption of the organics, which indicated a structural stability of the sorbent. The specific surface area was reduced from 450 m2/g to 189 m2/g on adsorption, and after desorption of the organics the specific surface area was 350 m2/g. The adsorption of COD was analyzed in a Langmuir model that described the data better than the empirical Freundlich model. This finding points towards that the adsorption occurred as a monolayer on the mp-Zr(OH)4. The free energy of adsorption (ΔG) is in the range of −20 kJ/mol < ΔG < 0. Entropy changes are ΔS > 0. The kinetics of the adsorption of COD is better described with a Quasi-second-order dynamic model than with a Quasi-first-order dynamic model, which elucidates its primary reliance on porous adsorption surfaces and incorporation of chemical adsorption.

Treatment of aqueous phase from hydrothermal liquefaction of municipal sludge by adsorption: Comparison of biochar, hydrochar, and granular activated carbon

Hydrothermal liquefaction (HTL) is promising for treating waste with high moisture, such as municipal sludge, and producing biocrude (a petroleum-like biofuel). However, a large amount of wastewater byproduct, HTL aqueous, is generated. The presence of hazardous compounds (e.g., phenolic compounds and nitrogenous organics) makes HTL aqueous the biggest bottleneck for full-scale implementation at treatment plants. This study investigated the adsorption of various pollutants, focusing on chemical oxygen demand (COD), in HTL aqueous to granular activated carbon (GAC), biochar, and hydrochar. It assessed the effect of pH, temperature, time, and adsorbent concentration on adsorption efficiency and identified proper adsorbent and process conditions for removing most of the pollutants from HTL aqueous. GAC showed the highest adsorption capacity (184 mg/g) for COD, surpassing biochar (44 mg/g) and hydrochar (42 mg/g). The adsorption of COD to all adsorbents followed pseudo-second-order kinetic and Freundlich isotherm, suggesting that the adsorption of HTL aqueous pollutants is a heterogeneous and multilayer process, limited by chemosorption. The adsorption was endothermic, favored by elevated temperatures and neutral pH. This means adsorption is more efficient and economical for treating HTL aqueous that is a hot stream at the large-scale and it saves chemical needs. Lastly, GAC was highly efficient and selective in removing harmful pollutants, such as COD (up to 66%), total phenolic compounds (up to 94%), pyrazines (up to 99%), pyridines (up to 100%), and cyclic ketones (up to 95%) while preserving valuable volatile fatty acids (VFAs) and ammonia for subsequent recovery. Removal of potentially inhibitory compounds and preserving VFAs are crucial for carbon recovery in anaerobic biological treatment of HTL aqueous. The results suggested the necessity of optimizing adsorbent dose for maximizing removal of specific group of inhibitory compounds in full-strength HTL aqueous for enhancing downstream biological treatment. Lastly, this study established the groundwork for HTL aqueous adsorption, elucidating its effectiveness and mechanism for pollutant removal.

Bone Char Adsorption of COD and Colour from Tannery Wastewater: Breakthrough Curve Analysis and Fixed Bed Dynamic Modelling

This study delves into the simultaneous adsorption of chemical oxygen demand (COD) and colour from tannery wastewater using bone char through a fixed bed column. The bone char, which was derived from cattle skulls, was characterised using the Fourier transform infrared spectroscopy, Braeuer–Emmett–Teller surface area analysis, and the scanning electron microscope/energy-dispersive X-ray spectroscopy. The effects of different process conditions, specifically, packed bed height (5, 10, and 15 cm) and flow rate (2, 5, and 8 mL/min), on the adsorption efficiency of the fixed bed column were assessed through breakthrough curve analysis. The results revealed that the efficiency of the column bed enhanced with increasing bed height and declined with increasing wastewater flow rate. The optimal operating conditions for COD and colour removal onto the bone char occurred at 15 cm bed height and 2 mL/min flow rate. The adsorption capacities at these conditions were 227.4 mg/g and 53.03 Pt-Co/g for COD and colour, respectively. The kinetics associated with the fixed bed adsorption of COD and colour onto bone char were elucidated through the fitting of the Thomas, Adams–Bohart, and Yoon–Nelson models to the experimental data. Among the three models, the Yoon–Nelson model gave the best prediction of the experimental data. Maximum adsorption efficiencies of 80.65% and 84% were attained for COD and colour removal, respectively, proving that bone char is a promising and ecologically friendly alternative adsorbent for the treatment of tannery wastewater.

Adsorption of chemical oxygen demand from surface water using bagasse activated carbon

Adsorption of chemical oxygen demand from surface water using bagasse activated carbon

Sustainable and optimized values for municipal wastewater: The removal of biological oxygen demand and chemical oxygen demand by various levels of geranular activated carbon- and genetic algorithm-based simulation

Municipal wastewater treatment in Mashhad, Iran, became increasingly concerned with removing hazardous organic matter. Granular activated carbon (GAC) units downstream are necessary to minimize chemical oxygen demand (COD) and biological oxygen demand (BOD) concentrations by 80–94% to meet effluent treatment; secondary treatment from municipal wastewater only reduces 47% of residual COD and BOD. This study analyzes different types of GAC for COD and BOD adsorption at different contact times and dosages. The dosage of GACs is 0.15, 0.2, and 0.25, with a surface area of 644.5 m2/g and a suitable size of 14.89 nm. Using and genetic algorithms-artificial neural networks (GA-ANNs), sustainable and optimization values are determined for municipal wastewater. Despite that, it can find solutions to difficult or impossible problems using traditional methods. Another advantage is that GA-ANN can be used to solve problems that have multiple objectives or constraints. They can be used either in conjunction with the biological process or as a tertiary stage after the advanced wastewater treatment process. GAC = 0.25 also confirmed the effectiveness of COD and BOD removal, removing 91% and 93%, respectively.

Tunning processes for organic matter removal from slaughterhouse wastewater treated by immediate one-step lime precipitation and atmospheric carbonation

Adsorption using unmodified/modified commercial activated carbons and constructed wetlands (CW) planted with Vetiveria zizanioides were evaluated as tuning processes for lowering chemical oxygen demand (COD) from slaughterhouse wastewater pretreated by the integrated process of immediate one-step lime precipitation and atmospheric carbonation. Powdered and granular activated carbons (PAC and GAC), and PAC and GAC incorporated with iron oxide nanoparticles (PACMAG and GACMAG) were used. COD removal using different adsorbent separation methods (i.e., sedimentation, filtration, or magnetic separation) was also evaluated. The adsorption results indicated that the best adsorbent doses and contact times of the studied adsorbents were 70 g L−1 and 5 min for PAC and PACMAG, and 60 g L−1 and 60 min for GAC and GACMAG. Under optimized conditions, GAC (75.7 ± 1.0%) and GACMAG (73.5 ± 2.1%) were more efficient than PAC (59.7 ± 1.0%) and PACMAG (59.0 ± 0.0%) in removing COD. The incorporation of iron oxide nanoparticles in GAC and PAC did not affect the adsorption of COD. The Temkin model was the best isotherm model found for PAC and PACMAG, while for GAC and GACMAG was the BET model. Pseudo-order n kinetic model was the best kinetic model found for all the adsorbents tested. There were no significant differences in the removal of COD between filtration and magnetic separations. Phytoremediation results indicated that increased COD removal efficiency occurred when the applied COD mass load decreased or when the bed depth was increased. Maximum COD removals of around 89.9–95.0% were achieved. Vetiveria zizanioides showed no signs of toxicity throughout the trials.

Removal of Colour and COD from vegetable tannery wastewater onto bone char– Effect of process parameters, adsorption mechanism, kinetics and equilibrium modelling

ABSTRACT In this study, bone char derived from head bones of cattle was used as an adsorbent in the removal of Chemical Oxygen Demand (COD) and colour from vegetable tannery wastewater. The char was characterized by proximate analysis, pHpzc, FTIR, BET surface area analysis and SEM-EDX spectroscopy. The effects of operational parameters (pH, contact time, adsorbent mass and temperature), the kinetics and isotherms of the adsorption process were investigated. Optimal conditions for maximum adsorption of COD (77.4%) and colour (98.01%) occurred at pH 2 after 60-minute contact time with 50 g of adsorbent at 25°C. The adsorption kinetics were analyzed using Elovich and the pseudo-first and – second-order models. The pseudo-second order model gave the best fit for the kinetic data. Application of the intra-particle diffusion and Boyd models to the kinetic data revealed that COD and colour adsorption onto the bone char were predominantly controlled by film diffusion. The Langmuir, Freundlich, Temkin and Redlich-Peterson isotherm models were applied. The Freundlich model best described the adsorption of COD and colour. The maximum monolayer adsorption capacities for COD and colour were 559.61 mg/g and 2011.76 Pt-Co/g, respectively. These results indicate that bone char can be an effective low-cost adsorbent in wastewater treatment.

Low-cost treatment method for organic matter and nutrients in landfill leachate.

In this study, the ability of low-cost composite adsorbents to treat organic compounds in terms of chemical oxygen demand (COD), total nitrogen (TN), and total phosphorus (TP) was investigated. The composite adsorbents were composed of washed sea sand (WSS), dewatered alum sludge (DAS), zero-valent iron (ZVI), and granular activated carbon (GAC). The removal efficiency of COD in landfill leachate by a composite adsorbent (composed of WSS (40%), DAS (40%), ZVI (10%), and GAC (10%) in weight) was 79.93 ± 1.95%. The corresponding adsorption capacity was 8.5 mg/g. During batch sorption experiments, the maximum COD removal efficiencies given by DAS, WSS, ZVI, and GAC were 16, 51.3, 42, and 100.0%, respectively. The maximum removal efficiencies of the above composite adsorbent for TN and TP were 84.9 and 97.4%, respectively, and the adsorption capacities were 1.85 and 0.55 mg/g, respectively. The Elovich isotherm model gave the best fit for COD, TN, and TP adsorption. This composite adsorbent can treat more than one contaminant simultaneously. The application of DAS and ZVI to make an efficient adsorbent for wastewater treatment would be a good re-use application for them, which would otherwise be landfilled directly after their generation.

Removal of pollutants from aqueous product of Co-hydrothermal liquefaction: Adsorption and isotherm studies

Hydrothermal liquefaction (HTL) is an attractive technology for the conversion of wet waste into biofuel and co-HTL has been touted to increase the quality of products. However, the recovery of energy from wastewater byproduct called aqueous co-product (ACP) is limited due to the presence of toxic inhibitory substances. Adsorption has been countenanced to remove these toxic compounds but there has not been a distinct comprehensive adsorption isotherm study to explain the interaction between the adsorbate molecules and the adsorbent sites. This study investigated the sorption mechanism of oxidizable reducing pollutants measured as chemical oxygen demand (COD); heavy metals (boron and copper); and phenols from ACP samples obtained from co-HTL of brewery trub (BT), and primary sludge (PS) onto granular and powdered activated carbon (GAC and PAC). Conventional isotherm models such as Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich were used for data analysis. Results indicated that the adsorptive capacity (qe) of PAC was greater than GAC in COD adsorption (BT−1947 > 234; BTPS−617 > 245; PS−289 > 207), boron adsorption (BTPS−70 > 7; PS−53 > 49), copper adsorption (BT−5 > 1; BTPS−3 > 2; PS−1.3 > 1.1) and phenol adsorption (BT−1340 > 356; BTPS−1587 > 253; PS−460 > 245) in mg/g, μg/g, μg/g, and μg/g respectively. Comparing the adsorption of pollutants onto PAC and GAC, this study observed that PAC followed the Temkin, and Dubinin-Radushkevich models in the adsorption of the four pollutants while GAC followed the Freundlich and Langmuir models in the adsorption of phenol and copper, and Temkin, and Dubinin-Radushkevich in the adsorption of COD and boron. This study proved that combining feedstock in HTL (co-HTL) does not only change the quality of the ACP but also changes the dynamics of the adsorption isotherms. The Free Energy Change (ΔG0) result showed a spontaneous reaction in the adsorption of copper and phenol. This study presents an adsorption equilibrium information for the interpretation of adsorption isotherms for the overall improvement of adsorption mechanism pathways and the effective design of adsorption systems for the treatment of ACP.

Adsorptive removal of organic pollutants from milk-processing industry effluents through chitosan-titanium dioxide nanoadsorbent-coated sand.

Milk-processing industry effluent (MPIE) poses severe problems for aquatic and environmental systems, especially in the South Asian region. Therefore, its treatment is of great interest. This study deals with the investigation of chitosan titanium dioxide nanoadsorbent (CTiO2) coated onto sand particles via calcination that are used to remove the emerging pollutants. The adsorptive properties of these developed adsorbents are compared with those of the nascent sand without coating as well as with the chitosan titanium dioxide nanoadsorbent coated sand (CTiO2-CS). Batch adsorption experiments were performed to investigate the percent reduction efficiency (%RE) of organic pollutants in terms of biological oxygen demand (BOD) and chemical oxygen demand (COD) from synthetic and real effluents. The maximum %RE of BOD (96.76) and COD (98.91) was achieved at 1.5M dose of CTiO2-CS, 120min of contact time, pH 6.5, an initial BOD concentration of 900mg/L, and an agitation speed of 400rpm. Similarly, the %RE of COD was found to be 86.75 for synthetic effluent and 90.97 for real effluent at initial COD concentrations of 8000mg/L. Pseudo-second-order and Langmuir models are found to be the best fits for BOD and COD adsorption. The diffusion model suggests that surface adsorption as well as intraparticle diffusion contribute to the actual adsorption process. Regeneration experiments were performed for four cycles, and CTiO2-CS was found to be the most regenerable adsorbent material. The performance of the adsorbent was compared with previous studies, and it was found to have excellent adsorption capacity. As a result, the developed filter bed could be used as a promising superadsorbent for the removal of organic load in MPIE.

Treating High COD Dyeing Wastewater via a Regenerative Sorption-Oxidation Process Using a Nano-Pored Activated Carbon.

Nowadays, the structural complexity of dyes used in the textile industry and the widely adopted water-saving strategy in the dyeing processes often fail plants’ biological wastewater treatment units due to chemical oxygen demand (COD) overload. To alleviate this problems, this study investigated a regenerable adsorption–oxidation process to treat dyeing wastewater with COD around 10,000 mg/dm3 using a highly nano-pored activated carbon (AC) as a COD adsorbent, followed by its regeneration using hydrogen peroxide as an oxidizing reagent. In addition to studying AC’s COD adsorption and oxidation performance, its operational treatment conditions in terms of temperature and pH were assessed. The results firstly demonstrated that about 50–60% of the COD was consistently adsorbed during the repeated adsorption operation before reaching AC’s maximum adsorption capacity (qmax) of 0.165 g-COD/g-AC. The optimal pH and temperature during adsorption were 4.7 and 25 °C, respectively. Secondly, AC regeneration was accomplished by using an initial peroxide concentration of 2.5% (by wt %) and EDTA-Fe of 2.12 mmole/dm3. The reuse of the regenerated ACs was doable. Surprisingly, after the first AC regeneration, the COD adsorption capacity of the regenerated AC even increased by ~7% with respect to the virgin AC. Thirdly, the results of a five-consecutive adsorption–regeneration operation showed that a total of 0.3625 g COD was removed by the 5 g AC used, which was equivalent to an adsorption capacity (q) of 0.0725 (= 0.3625/5) g-COD/g-AC during each adsorption stage. Based on the obtained results, a regenerable COD adsorption–oxidation process using a nano-pored AC to treat the high-textile-COD wastewater looks promising. Thus, a conceptual treatment unit was proposed, and its potential benefits and limitations were addressed.

Removal of COD in wastewater by magnetic coagulant prepared from modified fly ash.

In this paper, magnetic coagulants (Fe-AFA, Fe-BFA) were prepared, by mixing acid-modified fly ash (AFA) and base-modified fly ash (BFA) with magnetic components, as adsorbents for chemical oxygen demand (COD) in desulfurization wastewater and their adsorption kinetics and mechanism are reported. BET, SEM, EDS, FTIR, XPS, magnetization intensity, and batch experiments on coagulation kinetic and adsorption isothermal characteristics of magnetic coagulants were carried out. The results show that Fe-AFA has the best COD adsorption performance and superparamagnetism, and the COD removal amounts can reach 5.69mg/g, which is 112.43% higher than the raw fly ash. It was also found that the quasi-second-order kinetic and Langmuir equation could well describe the COD coagulation process. Thermodynamic tests results showed that the COD removal was a spontaneous, endothermic, and irreversible process. Reusability of magnetic coagulants was investigated. After five cycles, the COD removal amount of Fe-AFA was 2.74mg/g. These findings provide a feasible method for environmental-benign utilization of fly ash as low-cost adsorbents in wastewater treatment.

Modeling of linear alkyl benzene sulphonic acid removal from aqueous solution with fixed bed adsorption column: Thomas and Yoon–Nelson methods

AbstractBACKGROUNDIn Turkey, which is one of the world's top walnut producers, the volume of waste shell has increased in recent years as a result of escalating consumption. Globally, including in Turkey, cleaning products are the leading pollutants entering the aquatic environment. This study aimed to address both issues, by investigating the removal of Linear Alkyl Benzene Sulphonic Acid synthetic solution through a fixed‐bed adsorption column system embedded with the composite of a polyaniline‐supported activated walnut shell.RESULTSLinear Alkyl Benzene Sulfonic Acid removal efficiency was evaluated in terms of detergent and chemical oxygen demand (COD) parameters. Column performance increased with low flow rate, increased bed height and high inlet concentration. Optimum conditions were determined as 7.5 cm bed height, 10 mL min−1 flow rate, and 30 mg L−1 inlet solution concentration. Thomas and Yoon–Nelson models were applied to experimental data to estimate the column adsorption behavior. The Yoon–Nelson model (R2 &gt; 0.9) seemed fit to explain the adsorption column behavior. To understand the reuse capacity of the adsorbent a regeneration study was carried out, showing that the maximum adsorption capacity of the adsorbent (qtotal) decreased from 216 mg g−1 before regeneration to 6.4 mg g−1 after the third regeneration cycle.CONCLUSIONThis adsorbent has a high potential for detergent and COD adsorption from anionic aqueous solutions, and would be a good alternative for a pretreatment step. © 2022 Society of Chemical Industry (SCI).

Adsorption of chemical oxygen demand and ammoniacal nitrogen removal from leachate using seafood waste (green mussel shell) as low-cost adsorbent

Adsorption of chemical oxygen demand and ammoniacal nitrogen removal from leachate using seafood waste (green mussel shell) as low-cost adsorbent

Evaluation of Contemporary Computational Techniques to Optimize Adsorption Process for Simultaneous Removal of COD and TOC in Wastewater

This study was aimed at evaluating the artificial neural network (ANN), genetic algorithm (GA), adaptive neurofuzzy interference (ANFIS), and the response surface methodology (RSM) approaches for modeling and optimizing the simultaneous adsorptive removal of chemical oxygen demand (COD) and total organic carbon (TOC) in produced water (PW) using tea waste biochar (TWBC). Comparative analysis of RSM, ANN, and ANFIS models showed mean square error (MSE) as 5.29809, 1.49937, and 0.24164 for adsorption of COD and MSE of 0.11726, 0.10241, and 0.08747 for prediction of TOC adsorption, respectively. The study showed that ANFIS outperformed the ANN and RSM in terms of fast convergence, minimum MSE, and sum of square error for prediction of adsorption data. The adsorption parameters were optimized using ANFIS-surface plots, ANN-GA hybrid, RSM-GA hybrid, and RSM optimization tool in design expert (DE) software. Maximum COD (88.9%) and TOC (98.8%) removal were predicted at pH of 7, a dosage of 300 mg/L, and contact time of 60 mins using ANFIS-surface plots. The optimization approaches showed the performance in the following order: ANFIS-surface plots&gt;ANN-GA&gt;RSM-GA&gt;RSM.

Highly Effective Cow Bone Based Biocomposite for the Sequestration of Organic Pollutant Parameter from Palm Oil Mill Effluent in a Fixed Bed Column Adsorption System.

The reduction of chemical oxygen demand (COD) from palm oil mill effluent (POME) is very significant to ensure aquatic protection and the environment. Continuous adsorption of COD in a fixed bed column can be an effective treatment process for its reduction prior to discharge. Adsorption capacity of bone derived biocomposite synthesized from fresh cow bones, zeolite, and coconut shells for the reduction in the organic pollutant parameter was investigated in this study in a fixed bed column. The effect of influent flow rate (1.4, 2.0, and 2.6 mL/min) was determined at an influent pH 7. The optimum bed capacity on the fabricated composite of surface area of 251.9669 m2/g was obtained at 1.4 mL/min at breakthrough time of 5.15 h influent POME concentration. The experimental data were fitted to Thomas, Adams–Bohart, and Yoon–Nelson models fixed bed adsorption models. It was revealed that the results fitted well to the Adams Bohart model with a correlation coefficient of R2 > 0.96 at different influent concentration. Adsorption rate constant was observed to increase at lower flow rate influent concentration, resulting in longer empty bed contact time (EBCT) for the mass transfer zone of the column to reach the outlet of the effluent concentration. In general, the overall kinetics of adsorption indicated that the reduction in COD from POME using a bone-biocomposite was effective at the initial stage of adsorption. The pore diffusion model better described the breakthrough characteristics for COD reduction with high correlation coefficient. Shorter breakthrough time compared to EBCT before regeneration indicated that the bone composite was suitable and effective for the reduction in COD from POME using fixed bed column adsorption.

Wax and bentonite blends for prototyping industrial clay development: preliminary results

Wax and bentonite blends for prototyping industrial clay development: preliminary results

Adsorptive removal of dairy industrial pollutants by chitosan zinc –oxide nanoadsorbent- A comparitive study of artificial neural network and quadratic Box-Behnken design

Aim: To investigate the effect of operational parameters on the adsorption of biological oxygen demand (BOD) and chemical oxygen demand (COD) on to Chitosan zinc oxide (CZnO) nanoadsorbent using cost-effective and eco-friendly nanoadsorbent based effluent treatment processes. Methodology: CZnO nanoadsorbent particle was synthesized using chemical precipitation method. The nano size &lt;100 nm was achieved using high-speed cryo all mill, followed by the characterization using high-end instruments such as scanning electron microscope with elemental detection sensor (SEM-EDS), atomic force microscope (AFM), X-ray diffractometer (XRD) and Fourier transform inform infrared spectroscopy (FT-IR). Modeling and optimization of operational parameters were done with the artificial neural network (ANN) and Box-BehnkenDesign (BBD) statistical tools. Results: Optimized treatment combination for adsorption of BOD and COD were found at initial BOD and COD concentration of 100 and 200 mg l−1, pH of 7.0 and 2.0, adsorbent dosage of 1.25 mg l−1, contact time of 100 and 60 min. In these conditionsthe desirability values of 0.988 and 0.950 were found for BOD and COD adsorption. The maximum per cent reduction of BOD and COD by using CZnO nanoadsorbent was found to be 96.71 and 87.56. Two models such as Quadratic Box-Behnken and ANN were compared in term of sum of square errors (SSE), root mean square error (RMSE) and correlation coefficient (R2) values. Interpretation: The results obtained revel the well trained ANN model found to be more accurate in prediction of BOD and COD adsorption process parameters compared to BBD model.

Removal of organic pollutants from produced water by batch adsorption treatment

This paper studied the adsorption of chemical oxygen demand (COD), oil and turbidity of the produced water (PW) which accompanies the production and reconnaissance of oil after treating utilizing powdered activated carbon (PAC), clinoptilolite natural zeolite (CNZ) and synthetic zeolite type X (XSZ). Moreover, the paper deals with the comparison of pollutant removal over different adsorbents. Adsorption was executed in a batch adsorption system. The effects of adsorbent dosage, time, pH, oil concentration and temperature were studied in order to find the best operating conditions. The adsorption isotherm models of Langmuir, Freundlich and Temkin were investigated. Using pseudo-first-order and pseudo-second-order kinetic models, the kinetics of oil sorption and the shift in COD content on PAC and CNZ were investigated. At a PAC adsorbent dose of 0.25 g/100 mL, maximum oil removal efficiencies (99.57, 95.87 and 99.84 percent), COD and total petroleum hydrocarbon (TPH) were identified. Moreover, when zeolite X was used at a concentration of 0.25 g/100 mL, the highest turbidity removal efficiency (99.97%) was achieved. It is not dissimilar to what you would get with PAC (99.65 percent). In comparison with zeolites, the findings showed that adsorption over PAC is the most powerful method for removing organic contaminants from PW. In addition, recycling of the consumed adsorbents was carried out in this study to see whether the adsorbents could be reused. Chemical and thermal treatment will effectively regenerate and reuse powdered activated carbon and zeolites that have been eaten.Graphic abstract