Influence of flocculant polyacrylamide on concentration of titanium white waste acid by direct contact membrane distillation

• 作者: Biao Hu Jintao Ouyang Lanying Jiang
• 来源期刊: 中国化学工程学报（英文版）
• 年，卷（期）: 2020,（9）
• 所属期刊栏目: Materials and Product Engineering
• 页码范围: 2483-2496
• 页数: 14页
• 语种: 英文

摘要

Effort has been made to investigate the concentration of titanium white waste acid (TWWA) by direct contact membrane distillation (DCMD) and the focus is the influence of polyacrylamide (PAM) on membrane wetting and fouling.It was found that the presence of PAM in feed reduced membrane flux and retarded wetting development,even though its level in feed of H2SO4 solution was only 0.0002 wt％.The difference between the tests using pure water and neat PAM aqueous solution,respectively,as feed also indicated the above effect registered with PAM.AFM results showed that the addition of PAM in feed solution changed the membrane shell surface morphology.However,conclusive proof of the PAM existence in membrane cross-section and inner surface was not obtained,probably due to its low concentration in feed solution.Two approaches were tried to recover membrane flux.In comparison with operation w/o any treatment,HCl solution rinsing did not lead to obvious improvement in membrane flux recovery,while rinsing combined with gas purge has clearly delayed the degradation in acid concentration factor.Nevertheless,even the latter could not ensure long term stability.High tortuosity and low hydrophobicity of the membranes used were suggested as underlying causes and should be addressed in the future.