Selective and high efficient removal of Hg2+ onto the functionalized corn bract by hypophosphorous acid
2018
Lin, Guo | Wang, Shixing | Zhang, Libo | Hu, Du | Peng, Jinhui | Cheng, Song | Fu, Likang
A novel sorbent (HPACB) was prepared by functionalized corn bract with hypophosphorous acid and applied to selectively remove Hg2+ from aqueous solution. The HPACB was analyzed by Fourier transform infrared spectroscopy, scanning electron microscope and X-ray photoelectron spectroscopy. The adsorption properties of HPACB for Hg2+ were studied by batch experiments. The results showed that HPACB presented an excellent selectivity for Hg2+ from the competitive ions solution, viz. Cu2+, Cd2+, Co2+, Ni2+ and Zn2+. The isotherms and kinetics of adsorption process were well fitted to Langmuir and pseudo-second-order model, respectively. The results indicated that the adsorbing process was monolayer adsorption and the rate-limiting step was chemical sorption. The theoretical maximum adsorption capacity of HPACB for Hg2+ estimated from Langmuir model was 1293.71 mg/g, which was close to the experimental results. Moreover, the adsorbent can be easily regenerated and the removal rate was still higher than 92% after three cycles. The XPS analysis indicated that the complexation between Hg2+ and PO/POH was the main adsorption mechanism during the adsorption process, and the ion exchange also played an important role. These results suggested that HPACB was a potential sorbent for selective removal of Hg2+ from wastewater.
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