Removal of Hg(II) from Aqueous Solution by Adsorption Using Raw and Chemically Modified Rice Straw As Novel Adsorbents

Abstract

A novel mercapto-grafted rice straw (RS-GM) was synthesized and characterized against raw rice straw (RS-Raw). The RS-GM yielded a better Hg(II) biosorption performance compared to RS-Raw as the incorporated-mercaptan functional group presented a strong affinity toward Hg(II). The isotherm data correlated well with the Langmuir isotherm model having maximum biosorption capacity, q max of 103.10 mg/g and 161.30 mg/g for RS-Raw and RS-GM, respectively. The Hg(II) biosorption is thermodynamically feasible, endothermic, and spontaneous in nature. The biosorption kinetic data were best-fitted into the pseudo-second-order kinetic model. Further analysis suggested that the Hg(II) biosorption process is governed by the intraparticle and external mass transfer in which the film diffusion was the rate limiting step. The adsorption–desorption cycle was repeated four times by using diluted HCI as desorbing agent, and the results were comparable to the unused biosorbent. The removal of Hg(II), which was also done in the produced water, was found to be 96% by using RS-GM.

Sesame Husk as Adsorbent for Copper(II) Ions Removal from Aqueous Solution

“…To check quantitatively the validity of the used kinetic models in this study, a normalized standard deviation Δq e (%) is calculated by the following equation [225] …”

Marula seed husk (Sclerocarya birrea) biomass as a low cost biosorbent for removal of Pb(II) and Cu(II) from aqueous solution

“…This might be due to biosorption of metal ions onto the marula seed husk's exterior surface, and after that it became slow when the ions diffused into the interior surface. Furthermore, this can also be attributed to more vacant surface binding sites available for biosorption during the initial stage [30]. A maximum percentage metal removal of 86.7% was observed at 60 min for Pb(II) and 79.5% at 180 min for Cu(II).…”

Enhancing the Hg(II) Removal Efficiency from Real Wastewater by Novel Thymine-Grafted Reduced Graphene Oxide Complexes

“…Mercury (Hg) is one of the most hazardous environmental pollutants, which shows high toxicity even at low concentrations, 3,4 and exists in many metallurgical industry wastewater and releases into environments. Its non-biodegradable, fluidity, tends to accumulate in living tissues and easy transformed to methylmercury force us to search for an effective method for removal of aqueous mercury.…”