Chitosan-Immobilized Pumice for the Removal of As(V) from Waters

Abstract

A novel sorbent, chitosan-immobilized pumice, has been prepared for the sorption of As(V) from waters prior to its determination by hydride generation atomic absorption spectrometry. The success of the immobilization has been checked with such characterization techniques as scanning electron microscopy, thermal gravimetric analysis, and elemental analysis. Points of zero charge of the sorbents were determined with potentiometric mass titration. Batch-type equilibration studies have shown that the novel sorbent can be employed at a wide pH range resulting in quantitative sorption (>90 %) at pH 3.0-7.0 and greater than 70 % sorption at pH >8.0. These results demonstrate the advantage of immobilizing chitosan onto pumice, because, under the same conditions, pumice displays <20 % sorption toward As(V), whereas chitosan gives approximately 90 % sorption only at pH 3.0. The validity of the method was verified through the analysis of ultrapure, bottled drinking, and tap water samples spiked with arsenate; the respective sorption percentages of 93.2 (±0.7), 89.0 (±1.0), and 80.9 (±1.3) were obtained by batch-type equilibration. Arsenic sorption was also examined in the presence of common interfering ions resulting in competing effects of PO 4 3− and NO 3 − on As(V) adsorption.

Removal of As(III) and As(V) from water by chitosan and chitosan derivatives: a review

“…In this part, chitosan is mainly modified by acrylonitrile (Hanh et al 2015), cerium (Sharma et al 2014), sodium silicate (Boyacı et al 2010), montmorillonite (An and Dultz 2008), pumice (Turan et al 2014), mixed material (Kartal and Imamura 2005;Sabarudin et al 2005;Shinde et al 2013;Lin et al 2008;Liu et al 2012;Dhoble et al 2011;Dhanapala and Subramanianb 2015), film forming (Jana et al 2011), and Cu(OH) 2 /CuO (Elwakeel and Guibal 2015) (Table 6). Acrylonitrile has the cyano groups (-CN), which can be converted into amidoxime groups (-C(NH 2 ) = N-OH) by treating with hydroxyl amine (NH 2 OH) to improve the sorption capacity (Hanh et al 2015).…”

“…Acrylonitrile has the cyano groups (-CN), which can be converted into amidoxime groups (-C(NH 2 ) = N-OH) by treating with hydroxyl amine (NH 2 OH) to improve the sorption capacity (Hanh et al 2015). Cerium loading on the chitosan composite nanofiber can increase the exposure for effective sorption; therefore, it will improve the sorption capacity and reduce the sorption time (Turan et al 2014). As can be noted, immobilization of chitosan onto a supporting surface improves the surface area of sorbent with the number of functional groups available for sorption corresponding increasing (Hanh et al 2015;Boyacı et al 2010), and using sodium silicate as an immobilization matrix has the advantage to turn the immobilized amount of functional groups in a short synthesis time (Boyacı et al 2010).…”

“…At first, the sorption rate of the adsorbents was very fast, which was due to the smaller mass transfer resistance on the surface or the absence of internal diffusion resistance, and after this fast sorption period, the sorption rate decreased gradually and reaching the equilibrium need within 8 h or less (Hanh et al 2015;Turan et al 2014;Sharma et al 2014;Boyacı et al 2010;Liu et al 2011a, b). The sorption kinetics of arsenic ions onto the adsorbents was analyzed by the basis of the pseudo-second-order kinetic model, which is expressed by Eq.…”

“…The most frequently used isotherm model for sorption experimental data correlations is the Langmuir sorption model (Hanh et al 2015;Turan et al 2014;Boyacı et al 2010;An and Dultz 2008;Liu et al 2011a, b;Dhoble et al 2011;Dhanapala and Subramanianb 2015;Elwakeel and Guibal 2015) because of its simplicity, which is expressed by Eq. (28).…”

“…Chitosan is a natural polysaccharide obtained from chitin hydrolysis under an alkaline medium condition. It is non-toxic, renewable, and hydrophilic (Elwakeel 2010;Hasan et al 2008;Turan et al 2014). It is more efficient than chitin in terms of sorption capacity due to the presence of a miraculous number of free amino (-NH 2 ) groups, and it can serve as the coordination and reaction sites (Chiou and Li 2003;Annadurai et al 2008;Chatterjee et al 2005;Shepherd et al 1997).…”