Dongfeng Wang

Preparation of mixed rare earths modified chitosan for fluoride adsorption

Abstract This paper described the fluoride removal from water using a new adsorbent namely mixed rare earths modified chitosan (CR). Mixed rare earths mainly contained La followed by Ce which was analyzed by inductively coupled plasma mass spectrometry (ICP-MS). La(III)-modified chitosan (CL) was also prepared as control. For the batch technique, the effects of various parameters such as contact time, pH, adsorbent dose, initial fluoride concentration and co-ions on fluoride adsorption were studied. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to characterize adsorbents. It was observed that the fluoride adsorption capacity of CR (3.72 mgF − /g) was higher than CL (3.16 mgF − /g) at 2 h. The presence of co-ions such as bicarbonate and carbonate greatly affected the fluoride adsorption from water. Characterization experiments indicated the successful chelation between mixed rare earths and chitosan. The possible fluoride adsorption mechanism of CR was explained by a chemical reaction.

Effects of chitosan-RE3+-bentonite on growth of Chlorella vulgaris

Abstract Bentonite was modified with chitosan and REIs (La 3+ , Ce 3+ ) to form chitosan-RE 3+ -bentonite (CRB). CRB were characterized by DSC and FT-IR. And the inhibitory effects of CRB on the growth of Chlorella vulgaris were investigated. The results indicated that CRB could inhibit the growth of Chlorella vulgaris . The relative conductivity and the generation of malondialdehyde (MDA) increased. In addition, the superoxide dismutase (SOD) and peroxidase (POD) activities decreased. So CRB could be a promising algaecide agent.

As(III) Removal from Aqueous Solution Using a-Fe2O3-impregnated Chitosan Beads

A novel, bio-based sorbent for As(III), α-Fe2O3-impregnated chitosan beads (FICB), has been successfully synthesized and tested. Batch wise adsorption experiments were performed to evaluate the adsorption conditions, reusability as well as the effect of ionic strength and coexistence of other ions. The results indicated that the maximum adsorption capacity of FICB for As(III) was 4.46 mg/g at pH 5.0 and 20 °C with equilibrium adsorption time 8 h. The ionic strength and coexistence of other ions had no significantly effect on the adsorption of FICB. It was also revealed that FICB could be reused for at least 6 times with only 7% regeneration loss. This suggests that FICB is a very promising adsorbent for the removal of As(III) from aqueous solution.