Adsorbent For Removal Of Metal Ions Research Articles

Polyethylenimine modified graphene oxide hydrogel composite as an efficient adsorbent for heavy metal ions

Graphene oxide embedded calcium alginate (GOCA) beads were synthesized and further functionalized/reduced with polyethylenimine to increase their adsorption capacity towards heavy metal ions. The adsorption of metal ions such as Pb (II), Hg (II) and Cd (II) from aqueous solutions on the functionalized GOCA was studied under different experimental conditions and the results showed that the functionalized beads had high adsorption capacity compared to the non-functionalized beads. The maximum uptake of heavy metal ions was 602, 374, 181 mg/g for Pb (II), Hg (II) and Cd (II) ions respectively. The kinetics were found to follow the pseudo-second-order and the equilibrium data fitted well with the Langmuir adsorption isotherm. Thermodynamic parameters such as standard Gibbs Energy (ΔG0), standard enthalpy (ΔH0) and standard entropy (ΔS0) changes were calculated. Adsorption-desorption studies were carried out successfully up to five cycles using a mixture of HCl (pH 5) and 200 ppm CaCl2 solution as eluent. The newly synthesized beads showed superior metal ion removal capacity compared to alginate beads and polyethylenimine functionalized GO combined capability due to synergetic effect. The results suggest that the functionalized graphene oxide in calcium alginate bead matrix can be efficiently used as an adsorbent for metal ions removal from wastewater.

Adsorptive Removal of Metal Ions from Water using Functionalized Biomaterials.

Synthesis and modification of cost-effective sorbents for removing heavy metals from water resources is an area of significance. It had been reported that materials with biological origins, such as agricultural and animal waste, are excellent alternatives to conventional adsorbents due to their higher affinity, capacity and selectivity towards metal ions. These properties of biomaterials help to reduce or detoxify metal ions concentration in contaminated water to acceptable regulatory standards. Synthesis of novel, efficient, cost effective, eco-friendly biomaterials for heavy metal adsorption from water is still an area of challenge. In this comprehensive review, acompilation of patents as well as published articles is carried out to outline the properties of different biomaterials based on their precursors along withdetailed description of biomaterial morphology and various surface modification approaches. A detailed study of the performance of adsorbents and the role of physical and chemical modification in terms of enhancing their potential for metal adsorption from water is compiled here. The factors affecting adsorption behavior i.e., capacity and affinity of e biomaterials is also compiled. This paper presents a concise review of reported studies on the synthesis and modification of biomaterials, their use for heavy metal removal from waters and future prospects of this technology.

Preparation and characterization of CNSR functionalized Fe3O4 magnetic nanoparticles: An efficient adsorbent for the removal of cadmium ion from water

Cashew Nut Shell Resin (CNSR) coated magnetic nanoparticles are capable of removing heavy metals from waste water was synthesized by sol-gel process. The epoxidized CNSR was covalently bonded to Fe3O4 nanoparticle surface through Michael addition reaction between epoxy ring in CNSR and the amine group present at nanoparticle surface. The adsorbent was characterized by XRD, TEM, FT-IR, BET and MALDI-Mass measurements. The TEM images confirm that the magnetite nanostructures have spherical morphology with uniform size distribution. The average size of magnetic nanoparticles is 40nm. An FT-IR and MALDI-Mass spectrum clears the physical and chemical changes occurred during the Michael addition reaction between epoxidized CNSR and aminated Fe3O4 nanoparticle. The toxicity reduction or removal of Cadmium ion from waste water or drinking water source by the prepared CNSR-Fe3O4 nanoparticles shows an efficient adsorbent for metal ion removal. The heavy metal ion removal studies at various pH proved that the adsorbent can be used as an capable low cost ECO friendly material for removing even trace toxic Cadmium from contaminated water, particularly at basic pH.

Sorption of Cu2+ and Co2+ using zeolite synthesized from coal gangue: isotherm and kinetic studies

Adsorption of Cu2+ and Co2+ from aqueous solution using zeolite synthesized from coal gangue was examined at room temperature. Batch experiments were carried out to investigate the effects of contact time, initial ion concentration, and pH on the adsorption process. Under comparable conditions, the adsorption greatly depended on initial ion concentration and pH. Different isotherms were applied to describe equilibrium data, and the results turned out that adsorption data can be better fitted with Langmuir, Temkin, and Dubinin–Radushkevich models, indicating monolayer coverage of adsorption sites on the surface of zeolite NaX and a physical process for Co2+ and Cu2+ adsorption. Adsorption capacity calculated from Langmuir was 45.05 mg/g for Cu2+ and 44.53 mg/g for Co2+. The adsorption kinetic could be better described with the pseudo-second-order model, and the removal mechanism of Co2+ and Cu2+ by the synthesized zeolite NaX was governed by surface adsorption, film diffusion, and intra-particle diffusion. The work suggests that coal gangue-derived zeolite NaX can be used as an alternative economical adsorbent for metal ions removal.

Biosorptive uptake of Fe2+, Cu2+ and As5+ by activated biochar derived from Colocasia esculenta: Isotherm, kinetics, thermodynamics, and cost estimation

The adsorptive capability of superheated steam activated biochar (SSAB) produced from Colocasia esculenta was investigated for removal of Cu2+, Fe2+ and As5+ from simulated coal mine wastewater. SSAB was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller analyser. Adsorption isotherm indicated monolayer adsorption which fitted best in Langmuir isotherm model. Thermodynamic study suggested the removal process to be exothermic, feasible and spontaneous in nature. Adsorption of Fe2+, Cu2+ and As5+ on to SSAB was found to be governed by pseudo-second order kinetic model. Efficacy of SSAB in terms of metal desorption, regeneration and reusability for multiple cycles was studied. Regeneration of metal desorbed SSAB with 1N sodium hydroxide maintained its effectiveness towards multiple metal adsorption cycles. Cost estimation of SSAB production substantiated its cost effectiveness as compared to commercially available activated carbon. Hence, SSAB could be a promising adsorbent for metal ions removal from aqueous solution.

Hydrothermal Synthesis of Hierarchical Copper Oxide Nanoparticles and its Potential Application as Adsorbent for Pb(II) with High Removal Capacity

In this study, copper oxide nanoparticles with hierarchical morphologies (CuO) have been synthesized via a hydrothermal route. The morphology and microstructure of the as prepared samples were characterized by XRD, SEM, TEM, and SAED. CuO exhibited excellent performance for the removal of Pb(II) from aqueous solution. The effects of initial Pb(II) concentration and contact time on CuO were investigated from batch tests. The results indicate that the equilibrium adsorption data were best fitted by the Langmuir isothermal model, with the maximum adsorption capacity of 1428.5 mgg−1 which is found to be one of the highest values reported elsewhere in the literature; adsorption kinetics follows the pseudo-second-order kinetic equation and intra-particle diffusion model. A possible adsorption mechanism was predicted by using FTIR, EDX techniques. Large adsorption capacity for heavy metal ion and effective regeneration ability suggesting CuO is a very promising adsorbent for metal ion removal and wastewater cleanup.

Adsorption of cadmium (II) and zinc (II) on boron enrichment process waste in aqueous solutions: Batch and fixed-bed system studies

Adsorption performance of a waste material from boron enrichment process (BW) in removing zinc (II) and cadmium (II) ions from aqueous solution was studied in batch and fixed bed reactors. The optimum conditions for the treatment process were obtained by observing the influences of solution pH, contact time, initial solution concentration, and adsorbent dosage. The adsorption of the two metal ions showed rapid uptake on the waste in the initial 40min. Kinetic and equilibrium studies indicated that adsorption of the heavy metal ions from solution follows the sequence of Cd2+>Zn2+ and the Langmuir adsorption isotherm. The kinetic data were fitted closely to a pseudo-second-order model. Ion exchange between Ca2+ with Cd2+/Zn2+ was found to be the adsorption mechanism. Batch and column tests demonstrated that BW is a highly effective adsorbent for metal ion removal.

Optimization of parameters for adsorption of metal ions onto rice husk ash using Taguchi's experimental design methodology

Abstract The present paper deals with optimization of various batch parameters for the simultaneous removal of cadmium (Cd(II)), nickel (Ni(II)) and zinc (Zn(II)) metal ions from aqueous solutions by rice husk ash (RHA) using Taguchi's optimization methodology. Various adsorption parameters such as initial metal concentration of each metal ion ( C 0, i ), temperature ( T ), initial pH (pH 0 ), adsorbent dosage ( m ) and contact time ( t ) were varied at three levels to see their effects on the total adsorption of metals onto RHA ( q tot ). L 27 orthogonal array (OA) has been used for experimental design, and the results have been analyzed using signal-to-noise (S/N) ratio and Pareto analysis of variance (ANOVA). The parameter m has been found to be the most significant parameter with 47.38 and 37.78% contribution to the q tot and S/N ratio data. It is also observed that the interactions between C 0, i 's (i.e. C 0,Cd × C 0,Ni , C 0,Cd × C 0,Zn and C 0,Ni × C 0,Zn ) contribute significantly to both raw and S/N ratio data for simultaneous metal ions removal by RHA. All the parameters and their interactions considered are found to be statistically significant at 95% confidence level for the desired response characteristic, q tot . The study shows that the Taguchi's method is suitable to optimize the experiments for total metal ions removal. The total optimum adsorptive removal of metal ions were obtained with C 0, i = 0–100 mg/l, T = 40 °C, pH 0 = 6, m = 10 g/l and t = 60 min. The results showed that a multi-staged adsorptive treatment is necessary to meet the minimal discharge standards of metal ions in the effluent.

Evaluation of the adsorptive capacity of peanut hull pellets for heavy metals in solution

This study assessed the potential of peanut hull pellets to capture metal ions from wastewater and compared their performance to that of raw peanut hulls and a commercial grade ion-exchange resin. The uptake of Cu 2+, Cd 2+, Zn 2+, and Pb 2+ onto these media was investigated using a system of standardized batch adsorbers under steady state and transient rate conditions. The influence of the pelletizing process on the rate of metal ion sorption was evaluated by comparing the rate and extent of metal ion uptake onto peanut hull pellets vs. raw peanut hulls. Although a slight reduction in rate of adsorption was apparent for metal ion adsorption onto the pellets, equilibrium capacity was unaffected. Peanut hull pellets are an effective adsorbent for metal ion removal. Though their capacity is lower than that of commercial grade ion-exchange resins, their low cost makes them an attractive option for the treatment of low-strength metal ion waste streams in once-through fixed bed applications.