Modified Poly(4-vinylpyridine) Coated Silica Gel. Fast Kinetics of Diffusion-Controlled Sorption of Chromium(VI)

Abstract

A new sorbent has been prepared by coating alkyl quaternized poly(4-vinylpyridine) (PVP) on the high surface area of silica gel. The resulting granular sorbent was used to remove Cr(VI) from water. Batch experiments were conducted to determine the kinetics and sorption rate. The research demonstrated that the modified PVP coated silica gel (referred to as coated gel) could successfully remove chromium(VI) from solution and that the sorbent provided fast kinetics. A finite-bath diffusion-control model with changing bulk concentration was derived analytically for application to the coated gel sorption of Cr(VI). This model fitted the experimental data well. The sorption kinetics on modified PVP coated gel was found to be diffusion-controlled with a value of 5.8 × 10 -7 cm 2 /s for the product of the distribution coefficient and the effective diffusivity in the sorption of Cr(VI) on the coated silica gel.

Synthesis of a quaternary amine anion exchange resin and study its adsorption behaviour for chromate oxyanions

“…In acidic media, the uptake of chromate on RQA may follow the above mentioned reaction steps (2)-(4). In basic media, CrO 4 2− is the predominant species and its uptake by RQA may be represented as:…”

“…Alkali addition is required for the deprotonation of the chromate species. (b) Removal of exchange-phase CrO 4 2− with brine: R 2 CrO 4 + 2NaCl ↔ 2RCl + Na 2 CrO 4 (10)…”

“…Chromium compounds are extensively used in electroplating, anodizing operations in the surface finishing industry, corrosion control, oxidation, leather industry and various other industrial applications [1][2][3][4][5]. The effluents from these industries contain Cr(III) and Cr(VI) with the latter the most toxic form.…”

Synthesis, characterization and properties of ethylenediamine-functionalized Fe3O4 magnetic polymers for removal of Cr(VI) in wastewater

“…Many kinds of adsorbents for wastewater treatment have been developed, such as activated carbon [11], activated alumina [12], coated silica gel [13] and treated sawdust [14]. However, difficulties for separation rapidly and effectively after treatment from wastewater have been limited their application.…”

Sorption equilibrium of Cr(VI) ions by strong base anion exchangers with pyridine structures

“…24 Recently, a modified poly(4-vinylpyridine)-coated silica gel with very fast kinetics for Cr(VI) removal was prepared. 25 The primary objective of the present article is the study of the removal of Cr(VI) from aqueous solution by pyridine strong base anion-exchange resins with different functional groups, obtained by the quaternization reactions of 4-vinylpyridine (4-VP) : 8%divi-nylbenzene (8%DVB) copolymer, gel type, with halogenated compounds such as methyl iodide, ethyl iodide, and butyl iodide. The influences of functionality of the matrix and counterion type were investigated.…”