Chemically Modified Rice Husk Adsorbents, Characterization and Removal of Palladium(II) From Aqueous Solutions

Abstract

Rice husk (RH) was chemically modified to prepare different adsorbents for the removal of Pd(II) from aqueous solutions. Succinylated rice husk (RHS) was prepared by treating RH with succinic anhydride to introduce carboxylic functions to rice husk. RHS was used to anchor various polyamines, viz., ethylenediamine (ED) and diethylenetriamine (DT), to prepare new adsorbents, abbreviated as RHS-ED and RHS-DT, respectively. All these adsorbents were characterized by elemental analysis, PSD, FTIR, XRD, and SEM. The selectivity order for Pd(II) removal was found to be: RHS-DT>RHS-ED>RH>RHS. The Freundlich isotherm was found to fit adsorption data well for all the adsorbents under study. The monolayer adsorption capacities of for RH, RHS, RHS-ED, and RHS-DT obtained from Langmuir isotherm are 11.57, 7.710, 13.73, and 15.72 mg/g, respectively. The adsorption kinetic data were fitted well with pseudo-second-order kinetics model.

Chemically modified rice husk as an effective adsorbent for removal of palladium ions

“…The use of biosorbents possesses many advantaged including the recycling of waste materials and overcome the input of expensive chemicals [ 19 ]. Non-modified RH has low adsorption capacity toward metal ions [ 20 ]. Modification of RH has received important attention of researched to enhance its adsorption properties [ 21 ].…”

“…Modification of RH has received important attention of researched to enhance its adsorption properties [ 21 ]. Vyas et al prepared new sorbents based on modification of RH with succinic anhydride and different amines for removal of Pd 2+ from aqueous solutions [ 20 ]. However, poor adsorption capacity was achieved (7.7–15.7 mg/g) and the adsorption process was relatively slow (3 h).…”