Adsorption Capacity Of Adsorbent Research Articles

Efficient removal of diethyl dithiocarbamate with EDTA functionalized electrolytic manganese residue and mechanism exploration

The recycling of solid wastes is obligable as it can reduce the environmental pollution and prevent the diffusion of secondary pollution. In this study, a novel cheap adsorbent was prepared by modifying electrolytic manganese residue (EMR) with EDTA. The maximum adsorption capacity of adsorbents for diethyl dithiocarbamate (DDTC) was 133.46 mg/g under initial pH of 7.32 at room temperature. Adsorption kinetics study revealed the DDTC adsorption on EDTA-EMR is mainly controlled by chemisorption and isotherm studies implied the adsorption is a monolayer process. Mechanism exploration found that the DDTC molecules could enter into the holes of EDTA-EMR, and the transition metal-based sorption sites were crucial for the target molecule immobilization and chelation. High pH value (> 10) was found to have inhibited the adsorption capacity of adsorbent, which should be due to the fact that the decreasing of functional groups on adsorbents surface and the competition between DDTC and OH–. The ionic strength has negligible effect on the adsorption and the as-synthesized adsorbents showed excellent performance after five cycles. The overall results reveal that EDTA-EMR is a promising adsorbent ascribed by its low cost, good recyclability and excellent adsorption capacity.

Batch and column studies using doped polymer for elimination of Sodium 4-[4-(dimethylamino) phenyl] diazenyl benzene-1-sulfonate from wastewater

ABSTRACT In the present research Polyaniline (PANI) has been prepared by chemical polymerisation using oxalic acid (OA) as a dopant. Removal of Methyl Orange (MO), (Sodium 4-{[4-(dimethylamino) phenyl] diazenyl} benzene-1-sulphonate), from wastewater, has been carried out using Oxalic acid (OA) doped Polyaniline. Breakthrough curves have been obtained from column adsorption experiments. Maximum dye adsorption was witnessed at pH 3. Four isotherm models were studied for the adsorption data and the subsequent constants have been calculated. The mean adsorption energy estimated from the D-R isotherm model has been determined as 1.5 × 104 J mol−1. Thermodynamic investigations intimated the spontaneity as well as endothermicity, with an entropy change of (79 J mol−1 K−1). Kinetic experiments divulged the adsorption of the dye by a second-order mechanism. The film diffusion mechanism was predominating at all studied temperatures. The percentage saturation for PANI column is 99.98% with the adsorption capacity of adsorbent as 8.36 mg/g. The recovery of dye has been accomplished by 0.1 N NaOH through the exhausted column. Results demonstrated PANI to be an excellent adsorbent for the eradication of the hazardous dye from textile wastewater.

A porous multifunctional and magnetic layered graphene oxide/3D mesoporous MOF nanocomposite for rapid adsorption of uranium(VI) from aqueous solutions

A novel adsorbent, GO/Fe3O4/OPO3H2/PCN-222, was successfully synthesized via graphene oxide (GO) modification with magnetic particles, phosphorous-containing groups, and a mesoporous Zr-MOF, PCN-222 (PCN stands for Porous Coordination Network), respectively, to give the nominal composite. The last step was through a solvent-assisted ligand incorporation technique. Morphological, structural, and physicochemical properties of the hybrid material was assessed by FT-IR, PXRD, SEM/EDX, BET surface area, VSM, TGA/DSC, UV–vis DRS, and ICP-OES analyses. This solid was then used for dispersive solid phase extraction of uranium ions dissolved in water. Several parameters including pH of solution, extraction and desorption times, amount of adsorbent, and type and concentration of elution solvent were investigated and optimized. The maximum adsorption capacity of adsorbent was found to be 416.7mgg−1 (pH, 6.2; amount of adsorbent, 5.0mg; extraction time, 3.0min) beyond what was achievable with the individual components. In addition, various coordination modes between the multifunctional adsorbent and uranyl ions were investigated by DFT calculations in details, revealing some favorable non-covalent cation–π interaction and strong binding of free-base porphyrin, carboxyl and phosphorous-containing groups to the uranium ions. Under optimized conditions, high determination coefficient (R2=0.9994) was obtained and limit of detection and relative standard deviation were found 0.9μgL−1 and 2.7%, respectively.

Structural effects of amine polymers on stability and energy efficiency of adsorbents in post-combustion CO2 capture

Linear/branched polyethyleneimines (PEI) and their modified structures have been widely used to prepare CO2 adsorbents due to their low material cost and high amine content. However, few studies have been carried out to comprehensively understand the effects of polymer structures on the properties of adsorbents, especially other than CO2 capacity. In this study, we rigorously investigated the effects of polymer structures on the CO2 adsorption capacity, kinetics, adsorbent stability, and regeneration heat of adsorbents using four amine polymers with different molecular weights, amine distributions, and ppm-level metal impurities. Linear tetraethylenepentamine (TEPA) exhibited the highest CO2 adsorption capacity due to its low tertiary amine content. However, unlike common intuition, the high CO2 capacity of TEPA did not lead to high energy efficiency of the CO2 capture process because of excessively strong CO2 adsorption and substantial H2O co-adsorption under typical flue gas adsorption conditions. Furthermore, the use of TEPA led to the slowest CO2 adsorption kinetics and the fastest thermochemical degradation, limiting its practical applicability. In contrast, epoxide-functionalized branched PEI exhibited the lowest CO2 capacity, but enabled the most energy-efficient CO2 capture due to its moderate CO2 adsorption strength and suppressed H2O co-adsorption. It also exhibited the fastest adsorption kinetics and the highest stability. Conventional branched PEIs showed intermediate behaviors. The present results indicated that the CO2 adsorption capacity of adsorbents, which was the major focus of previous studies, should not be overemphasized for CO2 adsorbent development and other important engineering aspects (e.g., adsorption kinetics, thermochemical stability, and regeneration heat) need to be considered collectively.

Preparation and characterization of ternary Cu/Cu2O/C composite: An extraordinary adsorbent for removing anionic organic dyes from water

To find an expeditious adsorbent for removing residual organic dyes is an urgent task, because the protection of water resource does not permit of any delay. In this work, the ternary Cu/Cu2O/C composite with ultrahigh anionic dyes adsorption capacity was synthesized by a simple solvent-free method. The crystalline structure, chemical composition and adsorption feature of the Cu/Cu2O/C composite were systematically studied. The maximum monolayer adsorption capacity of Cu/Cu2O/C for methyl orange (MO) and acid blue 93 (AB93) is 1408.7 and 5385 mg g−1, respectively. Besides, the Cu/Cu2O/C composite can selectively adsorb anionic dyes from mixture of different dyes. A soaking process of hot water can easily release the loaded anionic dyes, and the adsorption capacity of invalid Cu/Cu2O/C composite can be recovered by a baking process. The equilibrium and kinetic studies indicate that the adsorption process is consistent with the Langmuir isotherm theory and pseudo-second-order model. The thermodynamics parameters (ΔG°, ΔH° and ΔS°) show that the adsorption process is spontaneous and exothermic in nature. Based on the experimental data and the characterization of Cu/Cu2O/C composite, it can conclude that the physical and chemical synergism effect co-exist in adsorption process, and chemisorption is the main rate limiting step. The excellent adsorption ability of Cu/Cu2O/C composite is mainly attributed to the interaction between sulfonic group and Cu (Cu0 or Cu1+). This work may shed light on developing high adsorption capacity of adsorbent for toxic organic pollutants removal and some special anion separation.

Mineral-derived Li4SiO4-based adsorbent for post-combustion CO2 capture: An experimental and kinetic investigation

Li4SiO4-based adsorbent is considered as a promising choice for the CO2 removal from power plants’ flue gases. However, the relatively high raw materials cost still limits its industrial applications. In this work, aiming to reduce the cost of Si-source, three novel natural occurring minerals including the pumicestone, the montmorillonite and the attapulgite were employed as Si-sources for the production of Li4SiO4-based adsorbents. The phase composition, surface morphology as well as the cyclic CO2 ad-desorption performance of obtained adsorbents were experimentally and kinetically investigated. It is found that the Si content of minerals directly determines the adsorption capacity of adsorbents, resulting in a relatively high and stable capacity of nearly 0.1 g/g within 22 cycles for the pumicestone derived adsorbent compared with other adsorbents obtained from minerals. Moreover, the excess Ca inside the minerals is found forming CaO, which is harmful to the desorption performance of adsorbent owing to the occurrence of Li–Ca–CO2 interactions. As a consequence, Si-source with high Ca content was proven inadaptable for the synthesis of Li4SiO4-based adsorbent, which provides guidance for the future selection of mineral Si-sources in this field.

Adsorption of Phenol Red and Remazol Brilliant Blue R by Coconut Shells (Cocos nucifera) and Ambarella Peels (Spondias dulcis)

The potential of agricultural waste materials for the removal of synthetic dye, Phenol Red (PR) and Remazol Brilliant Blue R (RBBR) from aqueous solution was investigated. One of the major pollutants of water pollution, dyes, which not only result in enormous damage to the water body but also impact the organism's health, as it is highly toxic and carcinogenic by nature. Agricultural wastes are sustainable adsorbents since they are availability and low cost, which can also replace the traditional activated carbon. Therefore, this study investigated the removal of PR and RBBR from dye solution by adsorption onto the treated adsorbent. Two best out of ten adsorbents were chosen through a screening process using RBBR as a tested dye. Coconut shells (Cocos nucifera) and ambarella peels (Spondias dulcis) were selected as the main adsorbent of this study since they achieved the highest removal rate compared to others. With the selected adsorbent, the experiment was continued to study the effect of different initial dye concentration, adsorbent dosage, contact time, pH, and particle size on dye adsorption. Results show that different parameters can affect the removal rate and adsorption capacity of adsorbent in a different way. The adsorption of dye from aqueous solution onto adsorbent was evaluated using Fourier transform infrared spectroscopy (FTIR) to investigate the functional groups of adsorbent before and after the adsorption process, and it found that the functional group would affect the effectiveness or removal rate and adsorption capacity of adsorbents. The present study indicates that 99.82% of PR with an adsorption capacity of 1.05 mg/g can be removed by 5-gram ambarella peels. While coconut shells had removed 75.78% of RBBR with an adsorption capacity of 7.96 mg/g for 21 hours. The results proved that these agricultural waste were promising materials as an alternative adsorbent for the removal of dye from aqueous solution.

Activated banana peel carbon: a potential adsorbent for Rhodamine B decontamination from aqueous system

Among various environmental pollutants, dyes have been reported to contaminate a large quantity of surface water. Rhodamine B, a widely applicable basic dye, is known for its hazardous impact on environment. The present study proposes the application of readily available waste banana peels for the remediation of water contaminated with Rhodamine B. The potential of prepared material to decontaminate Rhodamine B was examined as the function of various parameters. Variation in adsorption time, dose of adsorbent, pH value, and initial concentration has been observed under the influence of diverse condition. Quantitative adsorption was observed at a contact time of 60 min with an adsorbent dose of 12 mg. An increase in the initial dye concentration resulted in the enhancement of adsorption capacity of adsorbent. The value of enthalpy change was observed to be − 8.95 kJ mol−1. The negative value indicates the exothermic removal of Rhodamine B from water. Various models were applied to explain thermodynamics and kinetics of the process. Adsorption kinetics was better explained with pseudo-second-order model, whereas adsorption mechanism by intra-particle diffusion model reveals that pore diffusion was not only the rate-controlling step.

Adsorption of Cu (II)and Co (II) from aqueous solution using lignosulfonate/chitosan adsorbent

In practical application, the adsorption capacity, adsorption kinetics, recycling and production cost of adsorbent affect the application of adsorbent. In this study, porous lignosulfonate/chitosan adsorbent was prepared by simple radical polymerization of acrylic acid in the mixed solution of lignosulfonate and chitosan. The porous and large surface area of adsorbent provides more adsorption sites for heavy metal ions. A variety of characterization methods were used to characterize the appearance and structure of the adsorbent. Adsorbent can effectively adsorb heavy metal ions in aqueous solution, and has the best removal effect for Cu2+ and Co2+. The adsorption capacity of adsorbent for Co2+ is 386 mg g−1, and for Cu2+ is 283 mg g−1. 0.01 g adsorbent was used to adsorb 100 mg L−1 Cu2+, and the adsorption equilibrium was reached within 60 min. When the amount of adsorbent reaches 0.03 g, the removal rate of heavy metal ions of 100 mg L−1 can reach 99%. In this study, an adsorbent based on acrylic resin was developed.

Hierarchical multi-shell hollow micro\u2013meso\u2013macroporous silica for Cr(VI) adsorption

The development of easier, cheaper, and more effective synthetic strategies for hierarchical multimodal porous materials and multi-shell hollow spheres remains a challenging topic to utilize them as adsorbents in environmental applications. Here, the hierarchical architecture of multi-shell hollow micro–meso–macroporous silica with pollen-like morphology (MS-HMS-PL) has been successfully synthesized via a facile soft-templating approach and characterized for the first time. MS-HMS-PL sub-microspheres showed a trimodal hierarchical pore architecture with a high surface area of 414.5 m2 g−1, surpassing most of the previously reported multishelled hollow nanomaterials. Due to its facile preparation route and good physicochemical properties, MS-HMS-PL could be a potential candidate material in water purification, catalysis, and drug delivery. To investigate the applicability of MS-HMS-PL as an adsorbent, its adsorption performance for Cr(VI) in water was evaluated. Important adsorption factors affecting the adsorption capacity of adsorbent were systematically studied and Kinetics, isotherms, and thermodynamics parameters were computed via the non-linear fitting technique. The maximum capacity of adsorption computed from the Langmuir isotherm equation for Cr(VI) on MS-HMS-PL was 257.67 mg g−1 at 293 K and optimum conditions (pH 4.0, adsorbent dosage 5.0 mg, and contact time 90 min).

High-Performance Polyimides with Pendant Fluorenylidene Groups: Synthesis, Characterization and Adsorption Behaviour

High-performance polyimides (HPIs) were synthesized using various aromatic dianhydrides and fluorenylidene containing diamine via two-step polycondensation method and used as an adsorbent for the removal of dyes (Methylene blue (MB) and Rhodamine-B (Rh-B)). Various functional moieties (–O–, –(CF3)2, –(CH3)2) were incorporated through synthesis in the HPIs back-bone using various aromatic dianhydrides, which enhance the adsorption capacity of adsorbent. The structure and functional groups of HPIs were confirmed by NMR and FT-IR analysis. The surface morphology of HPIs and dye adsorbed-HPIs were determined using SEM–EDX analysis. The solution dye concentration was examined using a UV/Visible spectrometer. Adsorption parameters such as solution pH, initial dye concentration, adsorbent dosage, contact time and temperature were optimised. The effect of contact time and initial dye concentration data were used to evaluate the adsorption kinetic and isotherm parameters respectively. Types and mechanism of the adsorption process were predicted using adsorption kinetics and isotherm parameters. Adsorption of dye onto HPIs followed pseudo second-order kinetic model which was confirmed by the adsorption kinetic result. The maximum monolayer adsorption capacity (qe) of HPIs was calculated. From thermodynamic study, ΔG°, ΔS° and ΔH° were calculated, which could predict the nature of the adsorption process with respect to temperature. Adsorbed-HPIs waste was converted into a PET-adsorbed-HPIs composite to reduce the hazardous solid waste and examined the dye leaching properties.

Synthesis and characterisation of porous polyvinylpyrrolidone-co-poly(divinylbenzene) (PVP-co-PDVB) copolymer resins for the isolation of betalains from red beetroot

Betalain is a natural pigment with serious antioxidant and biological activities currently used as a food colourant, however; the isolation of this compound is difficult because of its instability. The research was aimed to synthesise and characterise the copolymeric adsorbents for the recovery of betalains by means of the solid-phase extraction (SPE) technique. For this purpose, divinylbenzene (crosslinker) was polymerised with polyvinylpyrrolidone containing vinyl groups by using free radical polymerisation, and toluene was used as a porogene. Polymeric resins in different polyvinylpyrrolidone/divinylbenzene (PVP/DVB) and toluene/divinylbenzene (Tol/DVB) rates were synthesised. The effects of these parameters on the polymerisation efficiency, size distribution, morphology, swelling properties and adsorption capacities of adsorbents were investigated in the later characterization stage. Adsorption tests were conducted by analyzing phenol adsorption in batch model systems. The KOD-4 coded adsorbent exhibited the best performance in adsorption tests with PVP/DVB and Tol/DVB ratios of 0.5 and 1.5, respectively. The betalains were recovered strongly from the red beet juice via the packed bed adsorption column system filled with KOD-4. Then, column reusability and regeneration were studied. In total, the prepared column system was used five times. Ultimately, the results of this study can lead to wide-scale application of betalain-enriched beetroot extracts in the food, pharmaceutical, and cosmetic industries due to their antioxidant and colourant properties as well as their biological activities.

Synthesis and Characterization of Zeolite–AMO Hybrid Composite Adsorbent by Using Simultaneous Gamma Irradiation for Uranium (VI) Removal from Aqueous Solutions

AbstractThe material of organic–inorganic hybrid polymers combine the functional organic and the advantages of a thermally stable and robust inorganic substrate, resulting in strong binding affinities toward selected metal ions and relatively high metal ion adsorption capacities. The aim of this work is to synthesize the polymer‐inorganic hybrid composite adsorbent base on amidoxime zeolite (zeolite–AMO) using simultaneous radiation technique; to characterize the adsorbent using FTIR and zeta potential; and to test the adsorption capacity of adsorbent for uranium (VI) using batch adsorption test in aqueous system. The solvent system of acrylonitrile monomer is water emulsion, with the concentration of 30%. The irradiation dose is 100 kGy with the dose rate of 2 kGy h−1. The hydroxylamine solution with the concentration of 6% in a mixture of water–methanol with ratio of 1:1 at 80 °C for 3 hours of reaction time uses for the amidoximation process. The result shows that the highest degree of grafting is 20.31%. Furthermore, the amidoxime density is 5.82 mmol g−1 and the optimum pH is 5.9. The sorption process follows the pseudo‐second‐order kinetic model and fits with the Freundlich model analysis.

Adsorption kinetics and isothermal adsorption model of crystal violet on modified red mud

The adsorption of crystal violet on red mud modified by sodium dodecylbenzene sulfonate (SDBS) was studied. The effect of the dosage of modified red mud on crystal violet adsorption was investigated. The results of kinetics and thermodynamics experiments showed that the adsorption of crystal violet by adsorbent fitted with the pseudo-second-order adsorption kinetic model better. The adsorption of crystal violet on modified red mud could be described by Langmuir and Freundlich models, and the adsorption was better in accordance with Freundlich isothermal adsorption model. According to the Langmuir adsorption model, the maximum adsorption capacity of adsorbent was 38.16mg/g at 303K.

Determination and Remediation of Selected Polycyclic Aromatic Hydrocarbons in Petroleum Contaminated Water

Determination and remediation of pollutants such as polycyclic aromatic hydrocarbons (PAHs) have not being fully regulated in Nigeria; hence contamination of surface water by such pollutant is a major concern. This study was designed to determine the level of selected PAHs in petroleum contaminated water using spectroscopic techniques and the efficacy of activated carbons made from Bambusa vulgaris and Oxytenanthera vabyssinaca. Bambusa vulgaris and Oxytenanthera abyssinaca were carbonized at 350OC and activated with Phosphoric acid (CBV350OC H3PO4) and Potassium chloride (COA 350OC KCl) as dehydrating agent respectively. The adsorbents were then used to remediate PAHs in petroleum contaminated water. Liquid-Liquid extraction procedures were used for extracting selected PAHs from sampled solutions. The batch experiment was performed to study the adsorption capacity of adsorbents at 5hrs contact time. Analysis of PAHs concentration for each sampling day was determined by GC-MS. Total PAHs in simulated wastewater did not show a clear trend, contrary to the expectation that there should be a progressive increase with time due to photolysis or photodecomposition of compounds or PAHs. COA 350OC KCl showed a range of 6.2-19.3% removal efficiency of each selected PAH with a total percentage efficiency of 27.7-70.8 for all days. For CBV350OC H3PO4 removal efficiency ranged from 10.26-19.30% for each selected PAH and a total efficiency of 50.8-100% for all selected PAHs for the 4 days intervals. The experimental result showed that adsorbent made from Bambusa vulgaris and Oxytenanthera abyssinaca and activated with H3PO4 and KCl as dehydrating agentrespectively can efficiently adsorb the selected PAHs in contaminated water. The study also revealed that PAHs in contaminated water increases with time due to photodecomposition, thus necessitating their treatment on time.

Removal of methylene blue dye and lead ions from aqueous solution using activated carbon from black cumin seeds

This work reports the preparation of carbon from black cumin seeds (BCC) and then activated with 10 and 20 % sulfuric acid (H2SO4) to obtain new adsorbents designated black cumin activated carbon (BCAC-10) and (BCAC-20) respectively for the adsorption of lead (Pb(II)) ions and methylene blue (MB) dye from aqueous solution. The adsorbents were characterized by scanning electron microscopy (SEM), Fourier transformed infrared (FIR), thermogravimetric analyzer (TGA), X-ray diffractometer (XRD) and Brunauer, Emmett and Teller (BET) analysis. The SEM images show that both activated carbon adsorbents (BCAC-10 and BCAC-20) have rough irregular surfaces with cavities. FTIR results show the (-COO−), (-NH2), (-HSO−4), (-C=O) functional groups were involved in the adsorption processes of Pb(II) ions and methylene blue (MB) dye . Nitrogen adsorption studies show that there is an increase in surface area and pore size for both BCAC-10 and BCAC-20 in comparison with BCC. The operational parameters (concentration, contact time, temperature and pH) of Pb(II) ions and MB dyes adsorption were assessed in batch mode. It was observed that the trends for Pb(II) ions and MB dye adsorption increased with increasing initial concentration of the solution, (i.e.) greater uptake was observed in solutions with higher initial concentration. Therefore the adsorption of Pb(II) ions with initial concentration of 100 mg/L was 17.19, 17.71 and 17.98 mg/g onto BCC, BCAC-10 and BCAC-20 respectively. Whilst for MB dye it was 11.63, 12.71 and 16.85 mg/g onto BCC, BCAC-10 and BCAC-20 respectively. The equilibrium data for Pb(II) ions and MB dye fitted Freundlich isotherm model onto BCC, BCAC-10 and BCAC-20. This suggested that the process involve multi-layer adsorption with interactions between the adsorbate and the adsorbents. The results show that the adsorption processes of Pb(II) ions and MB dye were rapid in the first 20 min. It was observed that the maximum adsorption trend of Pb(II) ions and MB dye was obtained at pH 9 which made the surface of black cumin seeds to be negatively charged and therefore making it easier to be attracted to positively charged Pb (II) ions and MB dye. Kinetic studies showed that the adsorption of Pb(II) ions and MB dye onto BCC best fitted; pseudo-first order model whilst BCAC-10 and BCAC-20 data fits; pseudo-second order. The estimated pore adsorption for Pb(II) ions onto BCC, BCAC-10 and BCAC-20 was 65.85, 94.28 and 78.43 % respectively whilst MB dye was 73.37, 70.82 and 95.74 % respectively. Temperature and thermodynamics data indicated that the adsorption capacity of adsorbents increase with increasing temperature and the enthalpy (ΔH°) values indicated that the adsorption of Pb(II) ions and MB dye on the adsorbents was endothermic reaction. The entropy (ΔS°) gave positive values which indicated the randomness and degree of freedom for Pb(II) ions and MB dye in aqueous solution. The free energy (ΔG°) values for the adsorption of Pb(II) ions onto BCC, BCAC-10 and BCAC-20 show an increase in negative values as the temperature increases.

Insight into the effect of structural characteristics of magnetic ZrO2/Fe3O4 nanocomposites on phosphate removal in water

ZrO2/Fe3O4 nanocomposites with magnetic properties were prepared by facile one-step coprecipitation. The different structures of synthesized nanomaterials were obtained by calcination in air at different temperature. The relationship between the structure properties of as-synthesized samples and their adsorption capacities for phosphate has also been explored in detail. Results indicate that amorphous magnetic ZrO2/Fe3O4 has a higher specific surface area, surface hydroxyl and saturation magnetization than that of ZrO2/Fe3O4 nanocomposites with a certain crystalline structure. The calcination temperature of the samples has not significant influence on the isoelectric point of synthesized materials. As-synthesized amorphous magnetic ZrO2/Fe3O4 has a phosphate adsorption capacity of 29.5 mg P/g at near neutral natural pH, which is higher than that of reported in most of literature. The adsorption capacity of adsorbent for phosphate is closely related to its specific surface area and surface hydroxyl. With the increase of calcination temperature, some parameters of prepared magnetic ZrO2/Fe3O4 nanocomposites decreased, such as the specific surface area, surface hydroxyl, saturation magnetization and the adsorption capacity to phosphate. However, the magnetic ZrO2/Fe3O4 nanomaterials have better repeatability for phosphate adsorption. At the same time, the adsorption of phosphate by magnetic ZrO2/Fe3O4 nanomaterials was also studied from the aspect of kinetics.

The utility of cocoa pods husk M45 (Theobroma cocoa) as adsorbent of heavy metals, iron (Fe) and copper in the laboratory wastewater

Adsorption is one of the alternative media for processing wastewater. The study aims to use cocoa pods husk M45 (Theobroma Cacao) as a biosorbent in reducing Fe (III) and Cu (II) ions content in the laboratory liquid waste. This research was carried out through two systems, batch and continuous systems. The batch system was conducted to determine optimum contact time, optimum pH, and adsorption capacity, whereas the continuous system was intended to determine the adsorbent height and the maximum flow rate of laboratory liquid waste. The methods used in this study were adsorption and filtration. The adsorption results were analyzed by Atomic Absorption Spectrophotometer (AAS). The results found that the optimum contact time and the optimum pH for the adsorption of metal ions by cocoa pods husk M45 were 90 minutes and 6, respectively. The optimum flow rate of the wastewater in the continuous system was 6.166 mL/sec with an adsorbent height of 15 cm in the 2-inch adsorption column. The adsorption capacity of adsorbent based on the Langmuir isotherm was 11.074 mg/g for Fe (III) and 28.4091 mg/g for Cu (II).

Synthesis of hybrid hydrogel nano-polymer composite using Graphene oxide, Chitosan and PVA and its application in waste water treatment

Abstract The present work aimed to synthesize Graphene oxide impregnated chitosan–PVA​ hydrogel nano polymer and its application to remove Congo red dye present in solution. Adsorption of dye on GO fabricated hydrogel polymer was conducted in batch system. Prepared Graphene oxide reinforced hydrogel polymer (GORHP) was characterized by analyzing FTIR and SEM. Swelling response of synthesized polymer composite were investigated at different pH. Final concentrations of dye in solution and adsorption capacities of adsorbent at various experimental conditions (adsorbent mass, solution pH and initial adsorbate concentration in solution) were evaluated. At pH 2, dye adsorption efficiency was found as 88.17%for 20 mg/L of Congo red solution using 6g/L dose at 140 rpm rotation speed and at neutral pH condition it was ≃ 81%. Different adsorption Isotherm models were analyzed mathematically. Kinetic study was performed and evaluated by following different mathematical model. Pseudo second order kinetic model gave better agreement for experimental and model value of q e . Results inferred that this synthesized polymer composite may be an efficient adsorbent for dye removal. The correlation between the independent variables associated with Congo red dye adsorption and the dependent parameters ware established by analyzing ANN model.

Effect of Wood Vinegar on Adsorption and Desorption of Four Kinds of Heavy (loid) Metals Adsorbents

Wood vinegar (WV) is a common agricultural additive used for treatment of soil and stimulation of plant growth. Phosphate rock powder (PR), coal fly ash (CFA), zeolite (ZE) and bentonite (BE) are the common adsorbents for heavy (loid) metals (HMLs)-contaminated soil treatment. The present study focused on the effect of desorption of Pb(II), Cd(II) and As(III) from adsorbents in the presence of WV. The experimental results revealed that the removal fractions of HMLs from adsorbents gradually decreased and then remained steady with the increase of dilution ratios of WV. Subsequently, the optimal additive concentration of WV on different adsorbents was obtained. The experiment results revealed that acetic acid was the dominating component in WV affecting adsorption capacities of adsorbents for HMLs. Moreover, the research took the first time to discover that the addition of WV effectively modified the structure of adsorbents to improve adsorption capacities for HMLs. Given the advantages of low cost and green products of WV, this study not only provided an effective guidance for rational management of agricultural and environmental safety, but paved a new path to modify the structure of adsorbents for better adsorption capacities for HMLs via addition of WV.