Three-dimensionally ordered macroporous cross-linked polystyrenes (3DOM CLPS) with 2-mercaptobenzothiazole (MBZ) groups attached directly or via hydrophilic spacer arms to frameworks were prepared for use as heavy metal ion adsorbents. The hydrophilic spacer arms are polyethylene glycol (PEG) chains with three different lengths. The functionalized 3DOM CLPS were characterized by SEM, FTIR, and elemental analysis. The results confirm that the MBZ groups have been introduced onto the pore wall of 3DOM CLPS directly or via PEGs, and the ordered structure was well preserved after functionalization. The functionalized 3DOM CLPS are effective adsorbents for the removal of heavy metal ions from solution, with adsorption capacities ranging from 0.25 to 1.14 mmol/g for silver (I) ions and 0.28 to 0.51 mmol/g for mercury (II) ions, respectively. The introduction of hydrophilic spacer arms between the 3DOM frameworks and the heterocyclic functional groups improves the adsorption capacities and adsorption kinetics. The adsorption capacities increase with the length of spacer arm. After regeneration by washing with acidic thiourea solution, the metal ion adsorption capacities of the regenerated 3DOM materials were on around 90% of the original capacities. POLYM. ENG. SCI., 52:972-978,
The removal of chromium(III) (Cr(III)) from industrial wastewater by various low-cost methods has been widely investigated. In this paper, a type of bio-adsorbent was prepared using rice straw modified by fermentation and simple chemical treatment. The aim is to detect the adsorption mechanism and characteristics on Cr(III) ions. The analysis shows that the bio-adsorbent possesses four modified characteristics for Cr(III) adsorption. The first one is the acquired physical adsorption involving concave and convex structures. The second one is the effects of the hydrogen bonding surface hydroxyl groups and the metal chromium ion with complexation. The third one is mainly caused by hydrophilic active groups that possess carboxyl and hydroxyl groups during microbial degradation to combine with ions. The final one is the bio-adsorbent had high adsorption for low concentration of Cr(III) ions. The highest removal of around 97.45% was obtained at pH 5.0, bio-adsorption dosage of 0.5 g L(-1), and initial Cr(III) concentration of 20 mg L(-1). The adsorption process followed the pseudo second-order model (R(2) > 0.99), while the isotherms were fitted to the Freundlich equation (68.1926 mg g(-1)), mainly by chemical adsorption. This study demonstrates the potential of using this biosorbent to remove Cr(III) from both synthetic and industrial wastewater.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.