Journal of South China University of Technology (Natural Science Edition) ›› 2011, Vol. 39 ›› Issue (6): 90-94.doi: 10.3969/j.issn.1000-565X.2011.06.016

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Flocculation-Photocatalysis Treatment of Secondary-Fiber Papermaking Wastewater

Shen Wen-hao  Ning Li  Chen Xiao-quan  Li Cui-cui   

  1. State Key Laboratory of Pulp and Paper Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2010-07-13 Revised:2011-02-24 Online:2011-06-25 Published:2011-05-06
  • Contact: 陈小泉(1963-)，男，博士，副教授，主要从事纳米材料的制备及应用研究． E-mail: xqchencn@scut．edu．cn E-mail:ppwhshen@ scut.edu.cn
  • About author:沈文浩(1967-) ，女，博士，副教授，主要从事环境监测及控制研究．
  • Supported by:

    国家自然科学基金资助项目( 61074109)

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Abstract:

In this paper,the flocculation-photocatalysis treatment of the mixed wastewater from secondary-fiber paper mill was carried out,with TiO2 colloid prepared by the hydrolysis of titanyl organic compound as the flocculant and the photocatalyzer. Then,the flocculation mechanism of TiO2 colloid and the optimal photocatalysis conditions were investigated. The results indicate that ( 1) TiO2 colloid particles with the average diameter of 13. 5 nm is of
high photocatalytic activity; ( 2) when the flocculation performs at a TiO2 dosage of 0. 025% ( mass fraction) with a pH value of 4,and when the photocatalysis performs at a TiO2 dosage of 0. 050% with a pH value of 3,the COD of wastewater sample decreases from 909. 7mg /L to 103.0mg /L,and the total COD removal reaches 88. 7%; ( 3) the flocculation of TiO2 colloid is mainly due to the bridging between TiO2 colloid and the fine fibers as well as the dissolved colloidal substances( DCS) in the wastewater; ( 4) the COD removal of TiO2 colloid is high in the earlier stage of photocatalysis,and then slowly changes after 6 hours; and ( 5) TiO2 colloid is a kind of reusable photocatalyzer and a small dosage of it helps to reduce the energy consumption and the cost of wastewater treatment.

Key words: titanium dioxide colloid, wastewater treatment, flocculation, photocatalysis