Initial Ferrous Ion Concentration Research Articles

Photo-Fenton process applied for the treatment of industrial wastewaters containing diclofenac: optimization with low iron ions concentrations and without pH control

Diclofenac (DCF) can cause several adverse effects in the environment and it should be removed from industrial pharmaceutical wastewaters. Advanced oxidation processes (AOPs) are promising methods for the DCF degradation. But, in many cases, AOPs require acidic pH. However, at this condition, DCF precipitates, which may hinder its oxidation. Thus, in this work, some AOP were studied for the DCF degradation, especially the photo-Fenton process, applying the experimental design technique (Doehlert matrix), operating without and with pH control (between 6.5 and 7.0). As independent variables, the initial ferrous ion concentration ([Fe2+]) and the molar addition rate of H2O2 (FH2O2) were evaluated. Empirical models were proposed and optimized conditions were determined without ([Fe2+] = 0.27 mmol L−1 and FH2O2 = 1.64 mmol min−1) and with pH control ([Fe2+] = 1.0 mmol L−1 and FH2O2 = 1.64 mmol L−1), with the following predicted mineralization percentages: 93% and 68%, respectively. So, photo-Fenton process without pH control presented the best performances. Furthermore, at this condition, iron concentration respects the limit value established by the Brazilian environmental legislation. That is, in this condition, additional processes, in order to remove iron ions, would not be necessary, that is very interesting for applications on an industrial scale.

Oxidative hydrolysis of Fe(Ⅱ) in the process of hydrothermal synthesis of hematite

Abstract Iron removal is an important step in zinc hydrometallurgy, and hematite process not only can effectively remove iron, but also is environmentally friendly and has certain economic benefits, so it has great application potential in zinc hydrometallurgy. The oxidative hydrolysis of Fe(Ⅱ) was studied by the change of ions in solution with different initial ferrous ion concentration. Meanwhile, the oxidation rates of Fe(Ⅱ) at different initial Zn(Ⅱ) concentrations were also studied. The results show that temperature has an important influence on the oxidative hydrolysis of Fe(Ⅱ). Increasing the temperature can inhibit the formation of complex and make more Fe(Ⅱ) precipitate directly in the form of hematite, which is not limited by the hydrolysis rate of Fe(Ⅲ). The oxidation reaction of Fe(Ⅱ) approximately conforms to the second order reaction rate. Zinc sulfate can promote the oxidation of Fe(Ⅱ). When the initial Zn(Ⅱ) concentration was 20, 40, 60 and 80 g/L, the oxidation kinetic constants of Fe(Ⅱ) were 2.433, 4.492, 10.106 and 14.857 L·mol−1·min−1, respectively.

Extracting copper and cobalt from non-ferrous residues by iron- and sulfur-oxidizing bacteria.

How to recycle metals from the waste resources becomes a hotspot all around the world. Non-ferrous residues, which was produced by non-ferrous meltingindustry, and various of Cu and Co compounds exist in the residues in the form of CuxOy, CuxSy, CoxSy. In order to efficiently extract valuable metals from the non-ferrous residues, this study investigated the bioleaching behavior of Cu and Co from non-ferrous residues, using iron-oxidizing bacteria (IOB, Leptospirillum ferriphilum CS13) and sulfur-oxidizing bacteria (SOB, Acidithiobacillus caldus S2) by controlling the microbial composition, initial pH, and initial ferrous ion concentration. The results showed that IOB had a better performance on extracting Cu and Co than that of SOB, especially for Cu. Furthermore, 77.7 and 79.8% of Cu and Co were extracted under the optimal ratio of the initial number of IOB and SOB (1:1) after bioleaching, which was more than that when bioleaching by any one of these two kinds of bacteria. However, the changes of initial pH and ferrous ion concentration could not significantly enhance bioleaching performance. The results indicated that bioleaching had a good performance on recovering of metals from non-ferrous residues and excellent application prospect for the cleaner resource recycling.

Kinetic degradation of amoxicillin by using the electro-Fenton process in the presence of a graphite rods from used batteries

This study reports the removal of amoxicillin (AMX) in aqueous media using the electro-Fenton process in the presence of a graphite cathode recovered from used batteries. The impact of the relevant parameters on the electro-Fenton process, namely the applied current intensity, the temperature, the initial concentration of AMX and the initial concentration of ferrous ions were investigated. The results showed that the optimal values were: I = 600 mA, T = 25 °C, [AMX] 0 = 0.082 mmol·L −1 and [Fe 2+ ] = 1 mmol·L −1 , leading to 95% degradation and 74% mineralization. The model parameters of AMX mineralization were determined using nonlinear methods, showing that it follows a pseudo-second-order kinetic. The Energy consumption (EC) calculated under the optimal values was found to be 0.79 kW·h·g −1 , which was of the same order of magnitude of those reported in other findings; while it is noteworthy that the electrodes used in our study are of a lower cost.

Treatment of simulated industrial pharmaceutical wastewater containing amoxicillin antibiotic via advanced oxidation processes

ABSTRACT The treatment of pharmaceutical industrial wastewaters, containing the antibiotic amoxicillin (218.29 mg L−1), via some advanced oxidation processes (POA), was studied. The H2O2 photolysis process presented the highest percentage of mineralization (97%), after the total reaction time (180 min). However, the photo-Fenton process showed the highest organic carbon removal rate, mineralizing 65% of the initial concentration, in 30 min. Because of this fact, this process was studied in more detail. The initial concentration of ferrous ions (0.03–1.00 mmol L−1) did not affect the performance of the photo-Fenton process, possibly operating using concentrations of below 15 mg L−1 (0.27 mmol L−1), that is the iron content limit for discharging wastewaters established in the Brazilian environmental legislation. Furthermore, experiments were performed according to the composite experimental design technique (Doehlert matrix), analyzing the following variables: (i) the inlet molar flow rate of H2O2 (FH2O2 ) and (ii) the initial concentration of ferrous ions ([Fe2+]). Besides that, the initial mineralization rate and the total organic carbon removal percentages, measured at 5, 10, 15 and 30 min of reaction, were chosen as the response variables. It was observed that FH2O2 was the most important variable in relation to the initial degradation rate. In the optimal conditions (FH2O2 = 3.27 mmol min−1 and [Fe2 +] = 0.27 mmol L−1), the photo-Fenton process achieved a percentage of organic carbon removal of 84%, in only 30 min of reaction, presenting an interesting potential for real industrial applications, combined, or not, with conventional technologies (as biological treatments, for example).

Optimization of Continuous Electro-Fenton and Photo electro-Fenton Processes to Treat Iraqi Oilfield Produced Water Using Surface Response Methodology

Considerable amounts of produced water (PW) is usually accompanied with the production of oil. Most countries with oilfields are generally water stressed countries. This study proposed electro-Fenton (EF) as alternative for the degradation of organic pollutants in PW. Continuous electro-Fenton processes was investigated using dimensionally stable anode Ti-RuO2/IrO2 and activated carbon fiber felt (ACFF) cathode. The effect of crucial process variables, namely, initial ferrous ions concentration (0.1-0.5 mM), current intensity (100-500 mA), and residence time (22-81 minutes) on the removal efficiency of COD was studied using contour and response surface plots. The experimental results were analyzed by analysis of variance (ANOVA). Multiple response optimization for continuous EF experiments reveals that at optimum conditions (initial ferrous ion concentration of 0.306 mM, current intensity of 156.6 mA, and residence time of 81.0 min) the COD removal efficiency was 73.33% and electrical energy consumption was 0.901 kWh/kg COD. Improvement of continuous EF process was investigated using UVA irradiation (Photoelectron-Fenton). It was found that COD removal efficiency for continuous EF was increased to 81.1% and 86.0% when using one and two UVA lamps (3 Watt each) respectively. It is concluded that EF is an effective process for treating produced water and further improvement can be achieved by photo assisting the process.

Removal of a mix of benzophenones and parabens using solar photo-Fenton and a cylinder parabolic collector in aqueous solutions

Benzophenones and parabens have been cataloged as emerging pollutants due to their potential activity as endocrine disrupting chemicals, and its evidenced presence in different bodies of water. In this sense, this paper presents the results about the use of the solar photo-Fenton technology at pilot scale using a cylinder-parabolic collector, in the removal of three benzophenones and two parabens in aqueous solutions, assessing the effects of the initial concentrations of ferrous ions and hydrogen peroxide. The response surface methodology was employed to determine, under the evaluated experimental range, the conditions that promote a higher removal of each pollutant individually, and the elimination of the dissolved organic carbon present in a mix of the target substrates. In general, results indicate that evaluated factors affect significantly the treatment performance, and that this kind of technologies could be a potential alternative for the treatment of wastewater containing organic pollutants.

STUDY ON SOME FACTORS OF MAGNETIC FLUID CHITOSANCOATED Fe3O4 NANOPARTICLES FABRICATION VIA HYDROTHERMAL METHOD

To optimize reaction conditions of hydrothermal preparation of crystalline magnetite(Fe3O4) nanoparticles, the influence of some experimental parameters (temperature, initialconcentration of ferric and ferrous ions, and heating time), and their interactions on the magneticnanoparticle formation was studied using response surface methodology (RSM), based on astatistical design of experiments (DOE). The variation in the particle diameter and crystallitesize of obtained magnetic nanoparticles (MNPs) with the synthesis conditions was examined andtransmission electron microscopy (TEM) and X-ray diffraction analysis. The results showed thatcrystallite size was greatly affected by temperature, ferric salt concentration and the heatingtime, whereas the particle diameter strongly depended on the heating time, and on the interactionbetween the initial ferrous/ferric ion molar ratio and the initial concentration of ferrous ions. TheMNPs produced by this method were the objects to coat surface with chitosan solution. Thechitosan coated MNPs are nearly spherical with a mean size from 10 to 20 nm depending on theexperimental conditions. RSM analysis showed that under optimized conditions, the chitosancoated MNPs with smallest size 13.43 ± 1.5 nm and saturation magnetization 68.12 emu/g atroom temperature were obtained under the hydrothermal temperature 165oC, heating time 2 h 55minute and ferric salt concentration 0.21 M.

Microbially assisted arsenic removal using Acidothiobacillus ferrooxidans mediated by iron oxidation

Abstract The aim of this investigation was to determine the efficiency of arsenic removal present in acidic water using the biochemical method in presence of Acidothiobacillus ferrooxidans bacteria and ferrous ions. The process includes the bio-oxidation of ferrous to ferric by bacteria with simultaneous conversion of arsenite to arsenate and its removal by chemical method. The experiments were carried out in shake flasks with or without A.ferrooxidans culture. The variables of the pH, temperature, cell density and initial concentration of ferrous ions in the growth medium of A.ferrooxidans bacteria were examined in the laboratory to determine how they affect the removal of arsenic. It was found that the maximum arsenic removal (80%–85%) occurred at ferrous ions concentration of 2 gL−1 at the temperature of 35 °C with the initial cell density of 3.66 × 107 cells/mL and initial pH value of 2.5 with 70%–75% bio-oxidation of ferrous ions. The results of scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses have confirmed the growth of bacteria and identify the nature of precipitate generated by the bacteria. The finding showed that arsenic can be removed considerably in this process in an efficient and greener way, but also removing efficiency was much more ( 80 % ) in acidic wastewater. The ANOVA and LSD statistical analysis were performed to assess any significant differences occurred among the four different levels of each variable. This study verified that combination of bio-oxidation with filtration improves the removal efficiency of arsenic.

Arsenic tolerance and bioleaching from realgar based on response surface methodology by Acidithiobacillus ferrooxidans isolated from Wudalianchi volcanic lake, northeast China

Background: Traditional methods of obtaining arsenic have disadvantages such as high cost and high energy consumption. Realgar is one of the most abundant arsenic sulphide minerals and usually treated as waste in industry. The aim of the present study was to screen an arsenic tolerant bacterium used for bioleaching arsenic from realgar. Results: An acidophilic iron-oxidizing bacterium BYQ-12 was isolated from Wudalianchi volcanic lake in northeast China. BYQ-12 was a motile, rod-shaped gram-negative bacterium with an optimum growth at 30oC and pH 2.5. 16S rDNA phylogeny showed that BYQ-12 was a new strain of Acidithiobacillus ferrooxidans . The inhibitory concentrations (ICs) of arsenite and arsenate were 32 and 64 mM, respectively. A significant second-order model was established using a box-behnken design of response surface methodology (BBD-RSM) and it estimated that a maximum arsenic bioleaching rate (73.97%) could be obtained when the pulp concentration, pH and initial ferrous ion concentration were set at optimized values of 0.95% w/v, 1.74 and 3.68 g/L, respectively. SEM, EDS and XRD analyses also revealed that there was direct bioleaching besides indirect electrochemical leaching in the arsenic bioleaching system. Conclusion: From this work we were successful in isolating an acidophilic, arsenic tolerant ferrous iron-oxidizing bacterium. The BBD-RSM analysis showed that maximum arsenic bioleaching rate obtained under optimum conditions, and the most effective factor for arsenic leaching was initial ferrous ion concentration. These revealed that BYQ-12 could be used for bioleaching of arsenic from arsenical minerals. Normal 0 21 false false false EN-US ZH-CN X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:Tabla normal; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:10.0pt; font-family:Times New Roman,serif; mso-ansi-language:EN-US; mso-fareast-language:ZH-CN;}

Removal Color Study of Toluidine Blue dye from Aqueous Solution by using Photo-Fenton Oxidation

The degradation of Toluidine Blue dye in aqueous solution under UV irradiation is investigated by using photo-Fenton oxidation (UV/H2O2/Fe+). The effect of initial dye concentration, initial ferrous ion concentration, pH, initial hydrogen peroxide dosage, and irradiation time are studied. It is found put that the removal rate increases as the initial concentration of H2O2 and ferrous ion increase to optimum value ,where in we get more than 99% removal efficiency of dye at pH = 4 when the [H2O2] = 500mg / L, [Fe + 2 = 150mg / L]. Complete degradation was achieved in the relatively short time of 75 minutes. Faster decolonization is achieved at low pH, with the optimal value at pH 4 .The concentrations of degradation dye are detected by spectrophotometer at ?max =626 nm. The order of photo degradation reaction under UV is the first order kinetics. The photo-Fenton degradation process was monitored by UV-visible spectrophotometer.

Experimental investigation, modeling, and optimization of combined electro-(fenton/coagulation/flotation) process: design of experiments and artificial intelligence systems

In this study, a combined electro-(Fenton/coagulation/flotation) (EF/EC/El) process was studied via degradation of Disperse Orange 25 (DO25) organic dye as a case study. Influences of seven operational parameters on the dye removal efficiency (DR%) were measured: initial pH of the solution (pH0), applied voltage between the anode and cathode (V), initial ferrous ion concentration (CFe), initial hydrogen peroxide concentration (CH2O2), initial DO25 concentration (C0), applied aeration flow rate (FAir), and process time (tP). Combined design of experiments (DOE) was applied, and experiments were conducted in accordance with the design. The experimental data were collected in a hand-made laboratory-scaleglass cylindrical batch reactor equipped with four graphite barcathodes, an aluminum sheet anode, an aeration pump equipped with an air filter and air distributer, a 150-rpm mixer, and a DC power supply. A DR% of 98 was achieved with a pH0 of 4, V of 10, CFe of 7.5, CH2O2 of 0, C0 of 140, and FAir of 0. The data were used for modeling using normal and reduced multiple regression models (MLR & r-MLR) and artificial neural networks (ANN & r-ANN). Further statistical tests were applied to determine the models’ goodness and to compare the models. Based on statistical comparison, ANN models clearly outperformed the stepwise multiple linear regression (SMLR) models. Finally, an optimization process was carried out using a genetic algorithm (GA) over the outperformed ANN model. The optimization procedure was used to determine the optimal operating conditions of the combined process.

Tunable functional hydrogels formed from a versatile water-soluble chitosan

A versatile water-soluble chitosan (WSC) was applied to construct two kinds of controllable functional hydrogels. Magnetic beads were prepared by physical cross-linking WSC with sodium alginate, soaking particles with ferrous chloride and being subjected to self-oxidation. Magnetic character of the beads was tunable by simply changing the initial concentration of ferrous ions. The beads could bind compounds that contained different charges. Their adsorption capacities for coomassie brilliant blue, rhodamine and hemoglobin were 1, 0.5 and 2.3mg/g respectively. Another kind of functional hydrogel was prepared through radical cross-linking reaction between WSC and a macromonomer (PVAM) derived from well-defined polyvinyl alcohol. The dynamic mechanical thermal analysis and thermogravimetric analysis results revealed that the mechanical strength and thermal stability of this hydrogel depended on the structure of PVAM. The capability to bind heavy metal ions of the hydrogel also relied on the structure of PVAM. The adsorption capacities of the hydrogels for Cu2+ and Pb2+ could reach 20.3 and 60.1mg/g respectively.

Removal Color Study of Toluidine Blue dye from Aqueous Solution by using Photo-Fenton Oxidation

The degradation of Toluidine Blue dye in aqueous solution under UV irradiation is investigated by using photo-Fenton oxidation (UV/H2O2/Fe+). The effect of initial dye concentration, initial ferrous ion concentration, pH, initial hydrogen peroxide dosage, and irradiation time are studied. It is found put that the removal rate increases as the initial concentration of H2O2 and ferrous ion increase to optimum value ,where in we get more than 99% removal efficiency of dye at pH = 4 when the [H2O2] = 500mg / L, [Fe + 2 = 150mg / L]. Complete degradation was achieved in the relatively short time of 75 minutes. Faster decolonization is achieved at low pH, with the optimal value at pH 4 .The concentrations of degradation dye are detected by spectrophotometer at ?max =626 nm. The order of photo degradation reaction under UV is the first order kinetics. The photo-Fenton degradation process was monitored by UV-visible spectrophotometer.

Empirical model for bio-extraction of copper from low grade ore using response surface methodology

The copper extraction in shaking bioreactors was modeled and optimized using response surface methodology (RSM). Influential parameters in the mesophilic bioleaching process of a low-grade copper ore including pH value, pulp density, and initial concentration of ferrous ions were comprehensively studied. The effect of leaching time on the response (copper extraction) at the 1st, 4th, 9th, 14th and 22nd days of treatment was modeled and examined. The central composite design methodology (CCD) was used as the design matrix to predict the optimal level of these parameters. Then, the model equation at the 22nd day was optimized using the quadratic programming (QP) to maximize the total copper extraction within the studied experimental range. Under the optimal condition (initial pH value of 2.0, pulp density of 1.59%, and initial concentration of ferrous ions of 0 g/L), the total copper extraction predicted by the model is 85.98% which is significantly close to that obtained from the experiment (84.57%). The results show that RSM could be useful to predict the maximum copper extraction from a low-grade ore and investigate the effects of variables on the final response. Besides, a couple of statistically significant interactions are derived between pH value and pulp density as well as pH value and initial ferrous ion concentration which are precisely interpreted. However, there is no statistically significant interaction between the initial ferrous ion concentration and the pulp density. Additionally, the response at optimal levels of pH value and pulp density is found to be independent on the level of initial ferrous concentration.

Electrochemical Process for Diazinon Removal from Aqueous Media: Design of Experiments, Optimization, and DLLME-GC-FID Method for Diazinon Determination

In the present study, electrochemical process was studied via removal of diazinon (O,O-diethyl O-2-isopropyl-6-methylpyrimidin-4-yl phosphorothioate) as an insecticide/ acaricide organic case study. Influences of three operational parameters including initial ferrous ion concentration, initial hydrogen peroxide concentration, and initial diazinon concentration were measured and optimized in diazinon removal process. Response surface methodology (RSM) was used to design the experiments. The experimental data collected in a laboratory-scaled batch reactor equipped with four graphite bar electrodes as cathode and an aluminum sheet electrode as an anode. Quantitative analysis of diazinon was done with gas chromatography equipped with flame photometric detector. Disperse liquid–liquid microextraction was used prior to gas chromatography in order to extraction and preconcentration of diazinon from aqueous media to extraction phase. Acetone and chlorobenzene were used as disperser and extraction solvent, respectively. Maximum diazinon removal efficiency of 87% (0.85mg mass removal) in C 0 of 2mg/L and 80% (120mg mass removal) in C 0 of 300mg/L was achieved under different experimental conditions. The obtained experimental data were used for model building by RSM approach. Finally, optimization process was carried out using RSM algorithm.

Electrochemical degradation of RB-5 dye by anodic oxidation, electro-Fenton and by combining anodic oxidation–electro-Fenton in a filter-press flow cell

This paper reports the removal of a recalcitrant and toxic dye, Reactive Black 5 (RB-5) by three methods; 1) anodic oxidation (AO) on Boron-Doped Diamond (BDD), 2) by electro-Fenton (EF) process where hydrogen peroxide was produced by oxygen reduction on reticulated vitreous carbon (RVC) electrodes and 3) by the combination of AO–EF. The BDD and RVC electrodes were fitted in a filter-press flow cell in recycle batch mode of operation. The experimental set-up for the AO and EF processes consisted of two electrolyte compartments separated by a Nafion membrane with the dye contained in the anolyte and the catholyte, respectively. The combined AO–EF process used only one electrolyte compartment. The colour and total organic carbon (TOC) removal were more efficient when the AO and EF processes were used separately than the combined process, AO–EF. The influence of current density and initial concentration of ferrous ions were examined. The lowest energy efficiency (208kWhkg−1) with the EF process was found when −0.4V vs. Ag/AgCl was applied to a RVC electrode and the concentration of Fe2+ was 1.0×10−4moldm−3 achieving total colour and 74% of TOC removals in less than 90min electrolysis. All proposed processes were able to promote high percentages of TOC removal following a pseudo-first order kinetic oxidation. The BDD electrode was the most effective material to remove RB-5 dye within 7.5min and presented the highest apparent rate constant (0.835min−1) with 82% TOC removal within 30min at an energy consumption of 291kWhkg−1 and 41.1mAcm−2 current density. In the case of the combined process AO–EF the electrodegradation rate of RB-5 was at least three times lower, apparent rate constant (0.269min−1), and 32% of TOC was removed with a high EC (682kWhkg−1). Therefore oxidation process applied separately was more efficient.

Response Surface Methodology Study on Magnetite Nanoparticle Formation under Hydrothermal Conditions

In a hydrothermal preparation of crystalline magnetite (Fe3O4) nanoparticles, the influence of the experimental parameters (initial molar ratio of ferrous/ferric ions, initial concentration of ferrous ions, and heating time), and their interactions, on the particle formation was studied using response surface methodology (RSM), based on a statistical design of experiments (DOE). As indices indicating particle formation and crystallization, the variation in the particle diameter and crystallite size with the synthesis conditions was examined. The crystallite size was greatly affected by both the initial ferrous/ferric ion molar ratio and the heating time, whereas the particle diameter strongly depended on the heating time, and on the interaction between the initial ferrous/ferric ion molar ratio and the initial concentration of ferrous ions. The results from a statistical analysis suggest that the polycrystalline Fe3O4 nanoparticles form via crystal growth and/or thermal aggregation, after nucleation during hydrothermal treatment.

マグネタイトナノ粒子の水熱合成における応答曲面法を用いた粒子径制御

A hydrothermal synthesis process for preparing crystalline magnetite （Fe3O4） nanoparticles was statistically analyzed to control the particle size, using response surface methodology （RSM） based on design of experiments （DOE）. The influence of the experimental parameters （initial ferrous/ferric ion molar ratio, initial concentration of ferrous ions, and heating time） and their interactions on the particle growth was evaluated through the analysis of variance （ANOVA） for the dynamic light scattering diameter. Furthermore, the multiple linear regression analysis （MLRA） was performed, and then the three-dimensional response surface plots were obtained. The particle size was found to be affected by the experimental parameters, in particular, the interaction between the ferrous/ferric ion molar ratio and the concentration of ferrous ions, suggesting that the particle growth mechanism is altered depending on the amount of ferrous ions. The particle size can be successfully controlled to a given target level using the obtained analysis results.

Kinetics of uptake of Fe(II) from aqueous solutions by Co/Mo layered double hydroxide (Part 2)

AbstractThe kinetics of the Fe(II) uptake by Co/Mo layered double hydroxide (Co/Mo-LDH) intercalated with carbonate (CO3)2− as an interlayer anion was studied. The results revealed that the maximum adsorption capacities were 29.5, 59.1, and 77.9 mg/g when the initial ferrous ion concentration was 25 mg/l at 298, 308, and 318 K, respectively. These results displayed a high efficiency of the Fe(II) uptake from aqueous solution at higher temperature. The adsorption isotherms were seen to be consistent with Langmuir’s adsorption isotherm. The equilibrium adsorption contact time was determined for Co/Mo-LDH. This suggested that the pseudo-first-order equation might not be sufficient to depict the kinetics of Fe(II) onto the Co/Mo-LDH, and the kinetics of adsorption of Fe(II) onto Co/Mo-LDH were best described by the pseudo-second-order model. Also, the paper discussed the thermodynamic parameters of the adsorption (Gibbs free energy, entropy, and enthalpy). Our results demonstrated that the adsorption process ...