Amine-functionalized adsorbents have attracted increasing interest in recent years for heavy metal removal. In this study, diethylenetriamine (DETA) was successfully grafted (through a relatively simple solution reaction) onto poly(glycidyl methacrylate) (PGMA) microgranules to obtain an adsorbent (PGMA-DETA) with a very high content of amine groups and the PGMA-DETA adsorbent was examined for copper ion removal in a series of batch adsorption experiments. It was found that the PGMA-DETA adsorbent achieved excellent adsorption performance in copper ion removal and the adsorption was most effective at pH>3 in the pH range of 1-5 examined. X-ray photoelectron spectroscopy (XPS) revealed that there were different types of amine sites on the surfaces of the PGMA-DETA adsorbent but copper ion adsorption was mainly through forming surface complexes with the neutral amine groups on the adsorbent, resulting in better adsorption performance at a higher solution pH value. The adsorption isotherm data best obeyed the Langmuir-Freundlich model and the adsorption capacity reached 1.5 mmol/g in the case of pH 5 studied. The adsorption process was fast (with adsorption equilibrium time less than 1-4 h) and closely followed the pseudo-second-order kinetic model. Desorption of copper ions from the PGMA-DETA adsorbent was most effectively achieved in a 0.1 M dilute nitric acid solution, with 80% of the desorption being completed within the first 1 min. Consecutive adsorption-desorption experiments showed that the PGMA-DETA adsorbent can be reused almost without any loss in the adsorption capacity.
"A large diversity of host adsorbent materials was presented in literature, wherein macroporous copolymers based on glycidyl methacrylate present an adequate choice due to the use of suspension polymerization as an alternative for production of spherical beads of different geometry, design of textural properties and possibility of ring-opening reaction of pendant epoxy group  . Up to this moment, functionalized macroporous glycidyl methacrylate copolymer has been studied as adsorbent for chromium  , copper , arsenic , indium , uranium  and Reactive Black 5 . Some recent studies have specifically investigated arsenic removal by anion exchange fibers and resins from water     . "
[Show abstract][Hide abstract] ABSTRACT: Optimization of the synthesis of cross-linked macroporous polymer impregnated with hydrous iron oxide and post-process of obtained material by application of freeze/drying technique, produces high performance adsorbent applicable for efficient arsenic removal. Characterization and analysis of adsorbent performances encompass material characterization, equilibrium and kinetic study, influences of interfering ions and modeling of adsorption data in ion free and competitive conditions. Kinetic study, i.e. fitting by Weber–Morris model and single resistance mass transfer model predicts intra-particle diffusion as a rate-controlling step. Thermodynamic parameters indicate endothermic, feasible and spontaneous nature of adsorption process. Competitive kinetic study in the presence of interfering ions shows low detrimental effect on both capacity and kinetic of arsenic removal. Visual MINTEQ modeling software was used for the prediction of adsorbent performances and interfering ion influences. Preliminary fixed-bed column study was accomplished by the use of Bohart–Adams, Yoon–Nelson, Thomas and Modified dose–response model. High arsenic removal capacity of 31.0 mg g−1 at 25 °C, and multi-cycle reusability of ER/DETA/FO/FD, significantly affects the affordability of techno-economic indicators based on the operating costs of the process.
Chemical Engineering Journal 11/2015; 279. DOI:10.1016/j.cej.2015.04.147 · 4.32 Impact Factor
"Consequently, the synthesized hydrogel membrane was utilized for removal of copper (II) from an aqueous solution in different reaction conditions in the presence of several different functional groups of chitosan and monomer, which act as chelate sites. Copper is extensively used in the electrical and semiconductor industries, and in the manufacture of fungicides and antifouling paints (Liu et al. 2006). The synthesized chitosan-graft-poly(N-allyl maleamic acid) hydrogel membrane can be widely used in industry, especially water treatment, as good adsorbent of industrial effluents containing copper. "
[Show abstract][Hide abstract] ABSTRACT: A chitosan-graft-poly(N-allyl maleamic acid) hydrogel membrane was prepared by radical polymerization in the absence of a cross-linker. The product was characterized by Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM) to confirm the formation of hydrogels. Transparent hydrogels have been observed to exhibit as much as 223.4 % swelling capacity, following pseudo-second-order kinetic models. The synthesized hydrogel membrane was subsequently utilized for removal of copper ions from an aqueous solution in the presence of several different functional groups. The effects on adsorption efficiency of various parameters such as time, temperature, pH, initial concentration of copper (II) solution, and amount of hydrogel were also investigated. The maximum adsorption capacity and efficiency were found to be 50.75 mg g−1 and 99.91 %, respectively, by the 0.004 mg adsorbent after 12 h of immersion in copper solution. Finally, the result showed that hydrogel membrane is pH sensitive to copper (II) adsorption and has maximum adsorption efficiency near to the pH of ground water.
Water Air and Soil Pollution 08/2013; 224:1624. DOI:10.1007/s11270-013-1624-z · 1.55 Impact Factor
"Exposure to cadmium released in food and drinking water will lead to cardiovascular and cerebrovascular diseases, calcareous bone and kidney dysfunction (Järup1 and Alfvén, 2004). Attempts have been made on developing techniques for cadmium removal from water involving adsorption, chemical precipitation, ion exchange, reverse osmosis, electrochemical treatments, hyperfiltration, evaporation and membrane separation (Chen et al., 2009; Liu et al., 2006; Jang et al., 2008; Chang et al., 2006). Adsorption technique is an attractive approach for water treatment, especially if the adsorbent is low-cost, convenient to separation and easily regenerated before its application (Mohammed et al., 2011). "
[Show abstract][Hide abstract] ABSTRACT: This study describes a new effective adsorbent for cadmium removal from aqueous solution synthesized by coating a shellac layer, a natural biodegradable and renewable resin with abundant hydroxyl and carboxylic groups, on the surface of iron oxide magnetic nanoparticles. Transmission Electron Microscopy (TEM) imaging showed shellac-coated magnetic nanoparticle (SCMN) adsorbents had a core-shell structure with a core of 20 nm and shell of 5 nm. Fourier Transform Infrared Spectroscopic analysis suggested the occurrence of reaction between carboxyl groups on the SCMN adsorbent surface and cadmium ions in aqueous solution. Kinetic data were well described by pseudo second-order model and adsorption isotherms were fitted with both Langmuir and Freundlich models with maximum adsorption capacity of 18.80 mg/g. SCMN adsorbents provided a favorable adsorption capacity under high salinity conditions, and cadmium could easily be desorbed using mild organic acid solutions at low concentration.
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