Synthesis Of ZIFs Derivative Materials And Application Of Printing And Dyeing Wastewater Treatment

With the vigorous development of China's textile industry,printing and dyeing wastewater with high chromaticity and complex composition,which is harmful to the environment,has become an environmental problem that people pay attention to.Zeolite-like imidazole framework materials(ZIFs)are a subclass of metal organic framework compounds(MOFs).Because of their high surface area,high chemical and thermal stability,adjustable pores and other characteristics,ZIFs are widely used in the treatment of printing and dyeing wastewater.In this thesis,cobalt-based ZIFs is used as precursor to synthesize a series of organic pollutants,and the adsorption and catalysis effects of organic pollutants in printing and dyeing wastewater of the prepared materials are investigated.the research contents are as follows:1.A hollow adsorbent ZIF-67@NiCo-LDH was prepared by using ZIF-67 as template and in-situ growth of layered double hydroxide(LDH).The BET specific surface area and pore volume of the adsorbent were 170.77m2/g and 0.39 m~3/g respectively.The experimental results show that when the p H value of methyl orange(MO)is 4 and the initial concentration is 1800mg/g,the adsorption capacity of ZIF-67@NiCo-LDH to MO is 1766mg/g within 15 minutes.The study also found that the adsorption kinetics of methyl orange on the adsorbent accords with the pseudo-second-order kinetic model,and the adsorption isotherm model accords with Langmuir adsorption isotherm model.In addition,NiCo-LDH@ZIF-67 can selectively adsorb MO from a mixed solution of MO and MB(methylene blue).2.Three samples were prepared by using three different forms of ZIFs modified by thioacetamide(TAA)as precursors.All three samples showed excellent catalytic rates for the catalytic degradation of 4-nitrophenol(4-NP).N-ZIF-(0: 1)@NiCo-LDH catalytic rate(kapp = 42.7×10-3/s)was much better than N-ZIF-(1: 0)@NiCo-LDH(kapp = 17.9×10-3/s)and NZIF-(1: 3.5)@NiCo-LDH(kapp = 24.3×10-3/s).When the concentration of Na BH4 is 0.2mol/L,the catalyst shows the best catalytic activity.In addition,N-ZIF-(0:1)@NiCo-LDH also showed excellent catalytic activity for degradation of MO and MB,with a reaction time of about 180 s.3.Mesoporous catalyst S-ZIF-(1:2.5)@Ni_xS_y was prepared using ZIF-(1:2.5)as precursor.the BET specific surface area and pore volume of the catalyst were 167.49 m2/g and 0.32 m~3/g respectively.The experimental results showed that S-ZIF-(1:2.5)@Ni_xS_y showed excellent catalytic rate(kapp = 22.3×10-3/s)for the reduction and degradation of 4-NP.In addition,S-ZIF-(1:2.5)@Ni_xS_y also showed good catalytic activity for degradation of Congo red(CR),MB and MO,completing the catalytic reaction within 60 s,60s and 90 s respectively.