| dc.description.abstract | The traditional wastewater treatment methods such as chemical settling method, advanced oxidation processes, and biological treatment required to use agents or adsorbents, which is highly cost effective. Therefore, in recent years, photocatalyst technology is used for the removal of the wastewater pollutants.
In this study, we have chosen the natural polysaccharide (starch and cellulose) due to their low-cost, low pollution, their (both unmodified and modified) enhanced affinity for zinc metal to synthesize zinc oxide (ZnO) on further pyrolysis (calcination). In the aspect of starch, The results indicated that cross-linking can indeed enhance the adsorption capacity for zinc. However, with the increase in the degree of crosslinking, the degree of carboxymethyl is descending. In the case of cellulose, the effects of temperature of the etherification, solvent and chloroacetic acid concentration were investigated respectively. The results showed that the optimal etherification temperature as 60 °C, ethanol as a modified solvent, and chloroacetic acid concentration as 0.65 M.
Considering the dyeing industry wastewater with high chroma, it is difficult to achieve the effluent standards. So we selected dye Congo red and methylene blue as the photocatalytic pollutants and the zinc oxide prepared from natural polysaccharide as photocatalyst in photocatalytic experiments. Results showed that zinc oxide that prepared by the carboxymethyl starch with 1% cross-linking agent, has higher degradation efficiency because of the larger specific surface area.
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