This study facilitates the synthesis process of a novel graft copolymer (flocculant) using carboxymethyl cellulose, acrylonitrile and N-vinyl formamide as raw materials. The carboxymethyl cellulose graft polyamidine (CMC-g-PAMD) can be used as new flocculant to replace the traditional polyacrylamide flocculant, which manifested its excellent flocculation and degradation efficiency. A five-membered cyclic copolymer was prepared by the graft copolymerization, and the synthesized flocculants were characterized by EA, TG-DTG, FT-IR, SEM and NMR, confirming the successful synthesis of the desired copolymers. The operation conditions for copolymerization were experimentally investigated, and the results indicated that the optimal initiator dosage, copolymerization temperature, amidinization temperature, acidification time and flocculant dosage were 4 g/L, 50°C, 90°C, 3 h and 60 mg/L, respectively. Compared with the traditional polyacrylamide flocculant, the CMC-g-PAMD presented an outstanding flocculation ability of 96.1% under its optimal operation conditions, which showed an enormous potential in the application of coalmine waste-water treatment. Graphical
Yujian Yao,Meng Li,Xingzhong Cao,Peng Zhang,Wen Zhang,Junfeng Zheng,Xuan Zhang,Lianjun Wang
A new sulfonated diamine monomer , 4,4′-((1,4-phenylenebis(methylene))bis(azanediyl))dibenzenesulfonic acid (PMABSA) was synthesized and used as the sole aqueous reactant to fabricate a novel reverse osmosis (RO) membrane with trimesoyl chloride (TMC), in place of conventional m -phenylene diamine (MPD). The separation performance of the PMABSA/TMC membrane was optimized by the response surface method (RSM) by means of evaluating the pure water permeability (PWP) and salt rejection (R) to NaCl, and optimal results of PWP of 1.18 ± 0.03 L m −2 h −1 bar −1 , and R of 98.2 ± 0.4%, respectively, were achieved at 1.55 MPa. Owing to the rigid benzene ring in the center of the molecule, which may have a blocking effect during the interfacial polymerization (IP) process, the resulting barrier layer was less compact and had low thickness. Both molecular dynamics (MD) simulation and positron annihilation spectroscopy (PAS) revealed the creation of sufficient free volumes in the sulfonated polyamide matrix. Regardless of the slightly lower water permeation, the PMABSA/TMC membrane exhibited a superior rejection ability to all the ions compared to that of commercial SW30HR (Dow Chemical) in a model seawater separating test. Overall, all the results indicated the great potential of the novel membrane as a new choice of non-MPD RO membrane for seawater desalination.
危险品化学品经营许可证（带存储）