Custom-tailoring tight nanocomposite membranes for advanced reclamation of hairwork dyeing effluent

Abstract

A novel combination of custom-tailoring tight nanocomposite membrane process with dual-stage pretreatment incorporating flocculation and ultrafiltration has been experimentally conceived for the advanced reclamation of seriously contaminated hairwork dyeing effluent (HDE). The hybrid system exhibited impressive advantages of qualified recycle rate of HDE (91.2%) and minimal environmental impact when taking both bearable membrane fouling and appropriate long-term separation performance into consideration. It was observed that after partial alternative doping of M-tolidine-H and continuous incorporating of carbon quantum dots, both skin features (smoothness, hydrophilicity and charge) and nanoporous loose body (porosity and apparent pore size) of the resultant membranes were improved synergistically. As a consequence, the optimal TFN-CQDs membrane showed high water permeance of 4.31 L m−2 h−1 bar−1, rejection for small-sized organics (≥97.3%) and salt (≥96.4%) and good antifouling ability (86.2% of flux recovery ratio) operated for 72 h, which were superior than those of most other reported permeate membranes. Besides, the economical and feasible pretreatment steps including less dosage (only 100 mg L−1) of biodegradable CLF-10 flocculant and cheap UF module made the optimized reuse process more attractive. Overall, this study has taken a concrete step forward on the road of realizing zero liquid discharge and advanced reclamation of HDE.