Study On The Character, Characterization And Preparation Of Hydroxy Metal Oxide Compound Materials For Arsenate Removal

Environmental concern on arsenic contamination has increased in the past few decades due to the increased awareness of its risk to plants, animals, and human health, the development of effective and economic materials for arsenic removal has become a hot topic in the environment field. In this study, ball-type arsenic composite absorbent of cellulose acetate/hydroxy metal oxide (CA/MO-OH) has been developed and prepared. Different kinds of method are used for the characterization of CA/MO-OH composite absorbent samples including SEM/EDX, XRD, FTIR, BET, Zeta potential instrument and so on. Moreover, batch adsorption experiments were conducted to investigate the arsenic adsorption performance. The following results were obtained:1) The CA/MO-OH composite absorbent was prepared, and its surface appearance were brown balls with diameter 3-5 mm. The optimized experiment showed the component ratio of cellulose acetate, acetone, hydroxy metal oxide, H2O, Mg(ClO4)2 and tween80 was 7:40:10:5:3:1 (qualitatively).2) The SEM photograph of CA/MO-OH composite absorbent showed that its surface has microporous and hydroxy metal oxide, and has honeycomb in its internal. The analysis of dispelled CA/MO-OH composite absorbent suggested that hydroxy metal oxide was embedded 59.93%. After hydroxy metal oxide was embedded, XRD analysis showed it remains amorphous, the EDX analysis showed the molar ratio Fe to Mn was 3, the result of BET test was specific surface area reduced from 232m2/g to 150m2/g, the Zeta potential test showed that the isoelectric point shifted from pH6.1 to pH6.8.3) The static experiments have been used to evaluate the arsenic adsorption efficiency of CA/MO-OH composite absorbent. Adsorption arsenic capacity of CA/MO-OH composite absorbent increased with a decrease of pH value; common cations could promote arsenic removal, the presence of anion PO43-、SiO32-、CO32- and F- affected the arsenic removal larger, specialy PO43- had an obvious negative effect on arsenic adsorption in the arsenic removal process; the maximum adsorption capacities for As(Ⅲ) and As(Ⅴ) were 74.36 mg/g and 31.48 mg/g, respectively, thermodynamics experimental analysis showed ΔH0>0, ΔS0>O, ΔGo<0, which suggested that the arsenic adsorption was a spontaneous, endothermic reaction and irreversible process; The results of kinetic experimental showed that the rate-limiting step was physical diffusion, the equilibrium time of adsorption As(Ⅲ) and As(Ⅴ) was 20h and 10h, respectively. And the CA/MO-OH composite absorbent had long using life; In the arsenic removal process, Fe was not detected, and dissolved-out Mn was below the national standard, so CA/MO-OH composite absorbent was a security in the process of using.