Preparation And Performance Study Of Polyamide Forward Osmosis Membrane

Forward osmosis technology is a new type of water treatment technology and be used in wastewater treatment.With the increasing depth of coal mining,coal mine safety accidents occur from time to time,and the shortage of drinking water directly endangers the lives of trapped personnel.Polyamide forward osmosis membrane is a double-layer membrane composed of polysulfone membrane and polyamide membrane,which has a series of advantages such as high strength,good acid and alkali resistance,low cost,et al.It is highly concerned about the development of a polyamide membrane material that can filter mine water to meet human drinking standards,which will definitely play an important role in emergency rescue of coal mines.In this paper,polysulfone-polyamide membranes were prepared by phase conversion method/interfacial polymerization method,and the polyamide membranes were modified by introducing nanoparticles such as sulfonated graphene,sodium dodecyl sulfate-elosite,titanium dioxide,et al.The chemical composition,microscopic morphology,surface roughness and hydrophilicity of polyamide membranes were analyzed by FIRT spectroscopy,Raman spectroscopy,field emission scanning electron microscopy,atomic force microscopy and contact angle measurement test.The effects of nanoparticles on the water flux,SO42-and F-retention rates and reverse salt flux of the polyamide forward osmosis membranes were investigated using simulated mine water from Shendong coal mine as samples.The main conclusions obtained are as follows:(1)The sulfonate group and hydroxyl group in SGO improved the hydrophilicity of polyamide membrane.The surface roughness and hydrophilicity of polyamide membranes gradually increased with the increase of sulfonated graphene addition.When the addition amount reached 3 wt.%,the surface roughness was the largest and hydrophilicity was the strongest.(2)the ridge-valley structure of the polyamide forward osmosis membrane was more obvious,and the permeation performance was significantly improved by introducing sulfonated graphene.With the addition increase of SGO,the water flux of the polyamide forward osmosis membrane increased up to 38.1 LMH;the retention rate of F-increased and that of SO42-decreased slightly;the reverse salt flux continued to decrease.(3)The anionic surfactants and hydroxyl groups in sodium dodecyl sulfate-elosite nanotubes improved the hydrophilicity of the polyamide membrane.With the increase of SDS-HNTs addition,the surface ridge-valley structure became larger,the surface roughness increased,and the hydrophilicity first increased and then decreased.At addition is 3 wt.%,the ridge-valley structure on the surface of the modified membrane was destroyed and an uncomplete ridge-valley structure was observed,resulting in an increase in surface roughness and a decrease in hydrophilicity.(4)The permeation performance of the polyamide forward osmosis membrane was improved by the introduction of SDS-HNTs.With the increase of sodium dodecyl sulfate-erudite addition,the water flux increased and then decreased up to 30.3 LMH,rising about the retention rate of SO42-and F-gradually decreased;the reverse salt flux decreased and then slowly increased.(5)Dense spherical particles were deposited on the surface of elosite modified polyamide ortho-permeable membrane by introducing polydopamine,and the surface roughness increased,and the permeability performance such as hydrophilicity and water flux,SO42-rate and F-rate were further improved.The water flux was improved by more or less 7.6%,and the SO42-retention rate was up to 89%.