A novel chitosan/clay/magnetite composite for adsorption of Cu(II) and As(V)

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

“…For most of the process of the sorptions (Gupta et al 2012;Wang et al 2014a, b;dos Santos et al 2009;Liu et al 2011a, Cho et al 2012), it will be better to agree with the Langmuir than other models. The Langmuir linear expression (Gupta et al 2009;Liu et al 2011a, b;Vu et al 2013;Wang et al 2014a, b) is given as follows:…”

“…Others combine iron with chitosan in all kinds of forms, and the sorption is close to the pH under the certain condition (Fagundes et al 2008;Vu et al 2013;Gupta et al 2013;Cho et al 2012;Hanh et al 2015;Wang et al 2014a, b). For As(V), the best sorption is between 2 and 5, and the sorption will decrease due to the positive or negative charging on the surface of adsorbent and adsorbate at high pH.…”

“…And in the removal process of the use of chitosan beads impregnated with iron, it adsorbs completely in about 6 h or in a shorter time 2 h, which depends on the adsorbent manufacturing procedure (dos Santos et al 2009;Neto et al 2013;Liu et al 2011a, b;Gupta et al 2012). Arsenic removing rate by composite materials and crosslinked chitosan is really rapid, and some reach the top after several minutes (Abou El-Reash et al 2011;Cho et al 2012;Wang et al 2014a, b). Chitosan-coated magnetic sand will reach the pseudo-equilibrium after about 2 h (Vu et al 2013;Gupta et al 2013).…”

“…As(III) species can possess only Lewis acid-base interaction, and the sorption occurs through inner-sphere complex mechanism with the positive site generated by Fe complexed with chitosan (dos Santos et al 2009;Neto et al 2013;Liu et al 2011b). The sorption capacity of As(V) decreases as pH increases, because positively charged amino groups will become deprotonated, and surface charge of the adsorbent became negative (Dambies et al 2002;Cho et al 2012;Seyed Dorraji et al 2014).…”

“…For the cross-linked chitosan, iron-chitosan-coated sand, chelating resin, and chitosan hollow fiber membranes, the pseudo-second-order equation (Liu et al 2011a, b;Cho et al 2012;Marques Neto et al 2013) is the best and it can be expressed as follows:…”