Synthesis of chitosan resin possessing 3,4-diamino benzoic acid moiety for the collection/concentration of arsenic and selenium in water samples and their measurement by inductively coupled plasma-mass spectrometry

A chitosan resin functionalized with 3,4-diamino benzoic acid (CCTS-DBA resin) was newly synthesized by using a cross-linked chitosan (CCTS) as base material. The adsorption behavior of trace amounts of elements on the CCTS-DBA resin was examined by the pretreatment with a mini-column and measurement of the elements by inductively coupled plasma-Mass spectrometry (ICP-MS). Arsenic(V) could be retained on the CCTS-DBA resin at pH 3 as an oxoanion of H(2)ASO(4)(-). Selenium(VI) is strongly adsorbed at pH 2 and pH 3 as an oxoanion of SeO42-. while selenium(IV) as HSeO3- is adsorbed on the resin at pH 3. The sorption capacities are 82, 64, and 88 mg g(-1) resin for As(V), Se(IV), and Se(VI), respectively. The effect of common anions and cations on the adsorption of As(V), Se(IV), and Se(VI) were studied; there was no interference from such anionic matrices as chloride, sulfate, phosphate, and nitrate up to 20 ppm, as well as from such artificial river water matrices as Na, K, Mg, and Ca after passing samples through the mini-column containing the resin. The CCTS-DBA resin was applied to the collection of arsenic and selenium species in bottled drinking water, tap water, and river water

Preparation and characterization of novel chitosan-based mixed matrix membranes resistant in alkaline media

In this work, mixed matrix membranes (MMMs) based on chitosan (CS) and different fillers (room temperature ionic liquid [emim][OAc] (IL), metallic Sn powder, layered titanosilicate AM-4 and layered stannosilicate UZAR-S3) were prepared by solution casting. The room temperature electrical conductivity and electrochemical response in strong alkaline medium were measured by electrochemical impedance spectroscopy and cyclic voltammetry (CV). The ionic conductivity of pure CS membranes was enhanced, from 0.070 to 0.126 mS cm21, for the pristine CS and Sn/CS membranes, respectively, as a function of the hydrophilic nature of the membrane and the coordination state of Sn. This hydrophilic and charge nature was corroborated by water uptake measurements, where only the introduction of IL in the CS membrane led to a water uptake of 3.96 wt %, 20 or 30 times lower than the other membranes. Good thermal and chemical stability in alkaline media were observed by thermogravimetric analyses and X-ray photoelectron spectroscopy analyses, respectively, and good interaction between CS and the fillers observed by X-ray diffraction, scanning electron microscopy and CV. Thus, thin CS-based MMMs (40–139 mm), resistant in high alkaline media, show higher conductivity than pure CS membranes, especially those fillers containing tin, and although the electrochemical performance is lower than commercially available anion-exchange membranes they have potential in pervaporation.This work has been funded by the Spanish MINECO through grants CTQ2010-20347, at the University of Alicante, and CTQ2012-31229 and RYC2011-08550, at the University of Cantabria. The authors gratefully thank Prof. Frank Marken, from the University of Bath (UK), for his advice on the electrochemical impedance characterization, and Dr. César Rubio, Dr. Carlos Téllez, and Prof. Joaquín Coronas, from the University of Zaragoza and the Instituto de Nanociencia de Aragón, Spain, for the UZAR-S3 sample and fruitful discussions

Gum karaya (Sterculia urens) stabilized zero-valent iron nanoparticles: characterization and applications for the removal of chromium and volatile organic pollutants from water

This paper illustrates a method for the stabilization of nanoscale zerovalent iron (NZVI) suspensions with a “green” biopolymer, Gum Karaya (GK). The stability, sedimentation, aggregation behavior and reactivity towards Cr(VI) and volatile organic compounds using NZVI–GK (GK stabilized NZVI) and bare NZVI, were assessed. The stabilization mechanism of NZVI–GK was demonstrated using ATR-FTIR, XRD, XPS, TEM, SEM, TGA and particle size analysis. The NZVI–GK nanoparticle suspension was found to be stable for at least three months, suggesting a superior stability rendering property of GK which forms a scaffold to prevent NZVI from aggregating. Batch experiments, centred on Cr(VI) reduction and degradation of volatile organic compounds, confirmed that NZVI–GK was more reactive than bare NZVI. Furthermore, XPS and ICP-MS results revealed that Cr(VI) was reduced to Cr(III) by NZVI–GK and the remaining Cr(III) in solution was adsorbed onto GK, thereby completely removing chromium from the contaminated water. Our study suggests that an important role is played due to the attributes of GK (which include non-toxicity, biodegradability and cost-effectiveness) in conjunction with the ability of NZVI to remove all chromium viz. [Cr(VI) and Cr(III)] coupled with the total degradation and removal of VOCs (cis-1,2-dichloroethene, perchloroethene and trichloroethene) from water

Selective Binding, Self-Assembly and Nanopatterning of the Creutz-Taube Ion on Surfaces

The surface attachment properties of the Creutz-Taube ion, i.e., [(NH3)5Ru(pyrazine)Ru(NH3)5]5+, on both hydrophilic and hydrophobic types of surfaces were investigated using X-ray photoelectron spectroscopy (XPS). The results indicated that the Creutz-Taube ions only bound to hydrophilic surfaces, such as SiO2 and –OH terminated organic SAMs on gold substrates. No attachment of the ions on hydrophobic surfaces such as –CH3 terminated organic SAMs and poly(methylmethacrylate) (PMMA) thin films covered gold or SiO2 substrates was observed. Further ellipsometric, atomic force microscopy (AFM) and time-dependent XPS studies suggested that the attached cations could form an inorganic analog of the self-assembled monolayer on SiO2 substrate with a “lying-down” orientation. The strong electrostatic interaction between the highly charged cations and the anionic SiO2 surface was believed to account for these observations. Based on its selective binding property, patterning of wide (∼200 nm) and narrow (∼35 nm) lines of the Creutz-Taube ions on SiO2 surface were demonstrated through PMMA electron resist masks written by electron beam lithography (EBL)

Préparation de billes de gel de chitosane imprégnées par des ions molybdate (application au traitement d'effluents arsenies)

Le contexte de cette étude est celui du traitement des eaux industrielles arséniées par des procédés d'adsorption. Ce travail présente la préparation d'un adsorbant spécifique et performant vis-à-vis de As(III) et As(V) en solution. L'adsorbant se présente sous forme de billes de gel, constituées par du chitosane fonctionnalisé avec des ions molybdate. Cette imprégnation apporte au support une séléctivité dans des solutions concentrées en métaux et en sels dissous. Le pH optimal de fixation des deux espèces est compris entre pH 2.5 et 4. A saturation, les capacités d'adsorption sont de 200 mg.g-1Mo pour As(V) et de 70 mg.g-1Mo pour As(III). Les facteurs limitants de l'adsorption sont la réduction chimique du molybdène sur le support et la présence de phosphate en solution.This work deals with the preparation of a new sorbent selective and effective for the adsorption of As(III) and As(V) in waste waters. The sorbent is made of chitosan gel beads impregnated with molybdate ions. This impregnation allows the sorbent to be very selective even with high concentrations of salts and heavy metals in solution. The adsorption of arsenic species is maximum between pH 2,5 and 4 with uptake capacities equal to 200 mg.g-1 Mo for As(V) and 70 mg.g-1 for As(III). The presence of phosphate ions and reducing agents in solution can depress greatly arsenic sorption. ESCA studies carried out on the samples have shown that the oxidation state of Mo and As were not affected during the adsorption process. SEM-EDAX analysis have demonstrated the homogeneous arsenic sorption in the whole volume of the sorbent. Complete and selective desorption of As(III) and As(V) was performed with a 0,1 M orthophosphoric acid solution. Renee, more than 10 adsorption-desorption cycles can be carried out with the same quantity of sorbent. The main limiting factor of the adsorption-desorption cycles is the release of molybdate ions during the arsenic sorption step. In order to validate the process, the impregnated chitosan gel beads were used for the removal of arsenic in a mine and semi-conductors waste waters. In spite of the complex composition of these waters, arsenic sorption was only 7 fold decrease.VILLEURBANNE-DOC'INSA LYON (692662301) / SudocSudocFranceF

Water-Insoluble Copolymer Based on N-Methyl-D-glucamine and Quaternary Ammonium Groups with Capability to Remove Arsenic

WOS: 000343867900014The synthesis and sorption performance of As(V) with a copolymer resin is presented. The resin was obtained via the radical polymerization of a 1:1 mixture of N-(4-vinyl benzyl)-N-methyl-D-glucamine and (4-vinyl benzyl)trimethyl ammonium chloride using N,N-methylene-bis-acrylamide as the crosslinker. The effect of pH, concentration, and time on the arsenic sorption was studied. The copolymer exhibited good performance over a wide pH range regardless of the initial concentrations. The equilibrium experiments presented better results under alkaline conditions (pH 9.0) compared with acidic conditions (pH 3.0). The kinetic sorption was quite fast, particularly at low arsenic concentrations. In addition, the arsenic anions were eluted with different acid/alkaline reagents, and the acid eluents exhibited the best results. (c) 2013 American Institute of Chemical Engineers Environ Prog, 33: 1187-1193, 20147FP-MC Actions Grant CHILTURPOL2 (PIRSES- GA-2009 Project) [269153]; FONDECYTComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT)CONICYT FONDECYT [1110079]; PIA [ACT-130]The authors thank 7FP-MC Actions Grant CHILTURPOL2 (PIRSES- GA-2009 Project, Grant No. 269153), FONDECYT (Grant No. 1110079), and PIA (ACT-130) for the financial support