Study on flocculation performance of grafted and cross-linked double modified starch IStD

Abstract

Using corn starch（St） as raw material，epichlorohydrin（EPI） as cross-linking agent and （2-methacryloxyethyl） trimethyl ammonium chloride（DMC） as grafting monomer，a grafted cross-linked double modified starch-based flocculant IStD was synthesized by two-step method. The effects of dosage，pH，percentage content of kaolin，flocculation temperature and flocculation time on flocculation performance of IStD were tested. The results showed that under the condition of the percentage content of kaolin 2%，the dosage 14 mg/L，pH=7，the flocculation temperature 25 ℃，and the flocculation time 1 h，the light transmittance of the supernatant could reach 91.7%. The flocculation mechanism of IStD was preliminarily discussed by observing the dispersion of kaolin particles in water before and after dosing. The results showed that there were both electric neutralization and adsorption bridging in the flocculation process，and the electric neutralization was the main one. When IStD and CPAM were combined to treat domestic wastewater，the transmittance and COD removal rate could reach more than 90%，which had certain practical value.

Keywords

• modified starch
• （2-methacryloyloxyethyl） trimethyl ammonium chloride
• flocculation