An Imprinted Organic−Inorganic Hybrid Sorbent for Selective Separation of Cadmium from Aqueous Solution

Abstract

A hierarchical double-imprinting concept was applied to the preparation of a new organic-inorganic hybrid sorbent for selective separation of Cd(II) from aqueous solution. In the prepared hierarchically imprinted sorbent, both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide) were used as templates. The sorbent was prepared through self-hydrolysis, self-condensation, and co-condensation of the cross-linking agent (tetraethoxysilicate) and the functional precursor (3-(2-aminoethylamino)-propyltrimethoxysilane) in an alkaline media followed by gelation. The selectivity of the sorbent was investigated by a batch competitive ion-binding experiment using an aqueous Cd(II) and Zn(II) mixture. The largest selectivity coefficient for Cd(II) in the presence of Zn(II) was found to be over 100; the largest relative selectivity coefficient between Cd(II) and Zn(II), over 200. The uptake capacity of the prepared hierarchically imprinted sol-gel sorbent and the selectivity coefficient are much higher than those of the sorbent prepared in the absence of CTAB-template. The sorbent possesses a fast kinetics for the removal of Cd(II) from aqueous solution.

Capturing Lithium from Wastewater Using a Fixed Bed Packed with 3-D MnO2 Ion Cages

“…11 The adsorbent plays a vital role in determining the performance of packed bed adsorption systems; however, the majority of adsorbents have a lower adsorption capacity for smaller cations, such as Li. 12 Moreover, many adsorbents have been used to remove Li(I) but with low capacities. Abe and Chitrakar 13 synthesized an adsorbent, called the LiSbO 3 precursor, and found that the adsorption capacity is only 1.0− 1.4 mg/g.…”

Recovery of Lithium from Wastewater Using Development of Li Ion-Imprinted Polymers

“…18 However, most adsorbents are nonspecific, showing low selectivity toward a particular metal. 19 Therefore, it is important to exploit a new adsorbent for selective separation of Li from aqueous solution.…”

Selective sorbent enrichment of nickel ions from aqueous solutions using a hierarchically hybrid organic-inorganic polymer based on double imprinting concept

“…13 In the first step, the complex formation was performed between Ni 2+ ions and those binding sites (-NH-and -NH 2 ) present in AAMDMS in the presence of CTAB. For this task, 0.550 g of NiCl 2 .5H 2 O and 1.46 g of CTAB were dissolved in 40 mL of deionized water.…”

“…12 These sorbents are known as hierarchically imprinted organic-inorganic sorbents because they utilize the imprinting effect twice (metal ion template and surfactant). Their application as selective materials are still in early stages and have been limited only for copper, 12 cadmium and mercury, 13,14 whose functional employed groups have been (3-(2-aminoethylamino)-propyltrimethoxysilane) and N- [3-(trimethoxy-silyl)propyl]ethylenediamine (TPED).…”