Application of response surface methodology to the chemical cleaning process of ultrafiltration membrane

• Published in: Chinese journal of chemical engineering 2016-05, Vol.24 (5), p.651-657
• Main Authors: Wang, Caihong, Wei, Aishu, Wu, Hao, Qu, Fangshu, Chen, Weixiong, Liang, Heng, Li, Guibai
• Format: Article
• Language: English
• Subjects: Chemical cleaning; Response surface methodology; Ultrafiltration; Water treatment; 中心复合设计; 化学清洗工艺; 响应面法; 应用; 次氯酸钠; 氢氧化钠浓度; 清洗过程; 超滤膜
• ISSN: 1004-9541; 2210-321X
• DOI: 10.1016/j.cjche.2016.01.002

A numerical model was established to predict and optimise the chemical cleaning process of Polyvinylidene Fluo- ride （PVDF） Ultrafiltration （UF） membranes with the results from the experiment that applied the Response Sur- face Method （RSM） and Central Composite Design （CCD）. The factors considered in the experimental design were sodium hydroxide （NaOH） concentration, sodium bypochlorite concentration （NaCIO）, citric acid concentration and cleaning duration, The interactions between the factors were investigated with the numerical model. Humic acid （20 mg· L-1） was used as the model foulant, and chemical enhanced backflush （CEB） was employed to sim- ulate the chemical cleaning process. The concentrations of sodium hydroxide, sodium hypochlorite, citric acid and cleaning duration tested during the experiments were in the range of 0.1%-0.3% 100-300 mg· L-1 1%-3% and 0.5-1.5 h, respectively. Among the variables, the sodium hypochlorite concentration and the cleaning dura- tion showed a positive relationship involving the increased efficiency of the chemical cleaning. The chemical cleaning efficiency was hardly improved with increasing concentrations of sodium hydroxide. However, the data was sharply decreased when at a low level of sodium hydroxide concentration. In total, 54 sets of cleaning schemes with 80% to 100K cleaning efficiency were observed with the R＆M model after calibration.