氢氧化镁混凝过程应用于活性黄X-R废水脱色研究

对氢氧化镁混凝过程应用于活性黄X-R废水脱色进行了研究,考察了p H值、药剂投加量、搅拌速度和时间对活性染料废水色度去除率的影响,同时运用i PDA在线监测系统对混凝过程中染料废水的絮体形成进行监测,并进一步探求了不同搅拌条件对絮体生长特性和混凝过程的影响。结果表明:对于色度去除率,其最佳p H值为12.0,在p H为11.5和12.0时最佳药剂投加量分别为144,216 mg/L。搅拌过程中快速搅拌最佳速度为200 r/min,时间为40 s,慢速搅拌最佳速度为40 r/min,时间为10 min。搅拌条件对混凝过程至关重要,搅拌速度和时间增加都会对絮体形成及增长产生负面影响。根据Zeta电位的变化可知,混凝的主要机制是电荷中和及吸附。

REMOVAL OF COLOR FROM REACTIVE YELLOW X-R WASTEWATER BY MAGNESIUM HYDROXIDE COAGULATION PROCESS

This article studied removal of color from reactive yellow X-R wastewater by magnesium hydroxide coagulation process，and discussed the influences of pH values，coagulant dosages and different mixing conditions on color removal efficiency． The floc formation of dye wastewater was monitored by the intelligent Particle Dispersion Analyzer ( iPDA) ，and further the effects of different stirring conditions on growth characteristics of floc and coagulation process were also discussed． The experiment results showed that the maximum removal of chrominance ratio appeared when pH of the solution was enhanced to 12. 0． The optimum magnesium ion dose was 216，144 mg /L for pH level reached to 11. 5 and 12. 0，respectively． The coagulation performance was better when rapid stirring speed at 200 r /min for 40 s，and low stirring speed at 40 r /min for 10 min． Stirring condition was essential for coagulation process． Increasing the stirring speed and time would have a negative impact on the floc formation and growth． Based on the changes of zeta potential，charge neutralization and adsorption were proposed to be the main coagulation mechanisms．