纳滤膜分离浓缩煤化工高盐废水

利用NF-HF和NF-HS纳滤膜对煤化工废水二级反渗透浓水进行处理,重点考察其对Cl与SO42-的分离效果、结垢离子的截留率以及膜抗污染性能,并采用STRO(卷式高压反渗透膜)对纳滤产水进行浓缩处理.实验结果表明,与NF-HS相比,NF-HF具有更优的Cl-/SO42-分离效果及钙、镁、硅离子截留效果和抗污染性能;NF...

Separation of coal-chemical brine using nanofiltration membranes

NF-HF and NF-HS nanofiltration membranes were employed to separate SO₄^2- from Cl^-in secondary reverse osmosis concentrate discharged from coal-chemical wastewater treatment plant. The separation of SO₄^2- from Cl^-, rejection of scaling ions and anti-fouling performance of the two types membrane were investigated. Spiral Tube Reverse Osmosis (STRO) was used to concentrate permeate of NF-HF. The results showed that NF-HF membrane had better separation Cl^- from SO₄^2- and rejection of scaling ions than NF-HS membrane, whose rejection were 3.38%-16.03% for Cl^-, 91.18%-97.16% for SO₄^2-, 90% for Ca²⁺, 80% for Mg²⁺ and 40% for SiO₂, respectively. Moreover, NF-HF showed excellent antifouling property. The operating pressure rose slowly from 3.2 MPa to 4.5 MPa after continuously running 336 h and the membrane flux reduced by 11%, which was recovered completely after alkaline washing. STRO could effectively concentrate the NF-HF permeate and reject organic matter, but the anti-fouling performance was poor. Therefore, separating and concentrating coal chemical wastewater with NF-DTRO (Disc Tube Reverse Osmosis) combination process is practicable.