Preparation Of Carboxylic Acid And Amide Copolymer Crosslinked Resin And Modified Activated Carbon Material And Its Application In Hard Water Softening

At present,with the development of the economy and society and the improvement of the living standard,people's requirements for water quality are increasing quickly,and the influence of water on the health and stability of life will be more prominent.However,the high hardness of water in daily life often causes harm to people's health.Therefore,the development of new hard water softening materials to protect people's life safety and health has become particularly important.In this thesis,a macroporous cross-linked chelating resin containing carboxylic ion and amide group was synthesized,a carboxylic acid and amide copolymer modified activated carbon material was prepared.The main contents are as follows:?1?Synthesis and Properties of Macroporous Cross-linked Chelating Resin Containing Carboxylic Ion and Amide GroupA macroporous cross-linked chelating resin containing carboxylic acid and amide was obtained by reverse suspension polymerization of monomeric acrylic acid?AA?and methyl acrylamide?MAA?and cross-linking agent N,N-methylene diacrylamide?MBA?.After neutralization reaction in sodium hydroxide solution,a macroporous cross-linked chelating resin containing carboxylic ion and amide group[P?MAA-AA-MBA?]was obtained.The as-prepared materials were characterized by FE-SEM,FTIR,and Brunauer-Emmet-Teller?BET?analyses.Cross-section and surface analysis of the synthesized P?MAA-AA-MBA?by FE-SEM revealed that the pores inside P?MAA-AA-MBA?are rich,varied,and widely distributed,its surface is flocculent,its specific surface area is large,and its contact with water is better.From FTIR spectrum analysis,we know that the monomers and the cross-linking agent are well cross-linked and polymerized.BET analysis showed that the specific surface area of P?MAA-AA-MBA?prepared under optimized conditions could reach 85 m²/g.The ion exchange performance test of P?MAA-AA-MBA?showed that its ion exchange capacity enhances with the increase of its specific surface area.The maximum ion exchange capacity of P?MAA-AA-MBA?under the optimized conditions for calcium and magnesium ions could reach 400 mg/g?As CaCO₃?.The adsorption function regeneration test of P?MAA-AA-MBA?showed that after it saturatedly adsorbed calcium and magnesium ions in water its adsorption capacity for calcium and magnesium ions could reach almost 100%recovery via immersing it in the saturated salt water.The adsorption capacity of P?MAA-AA-MBA?for calcium and magnesium ions in water is almost not reduced after 5 consecutive saturated adsorption-salt water immersion.This showed that P?MAA-AA-MBA?could be reused many times and has a very long service life.?2?Synthesis and Properties of Carboxylic Acid and Amide Copolymer Modified Activated CarbonFrom above research project,we know that P?MAA-AA-MBA?can adsorb calcium and magnesium ions very quickly and efficiently.However,the reverse suspension polymerization was used in the synthesis process in which cyclohexane was used as the solvent and the reaction temperature was high,leading to a large number of high concentration organic wastewater and high energy consumption during the process of enlarging production.Therefore,on the basis of the research on the synthesis and properties of P?MAA-AA-MBA?,we changed the surface properties of activated carbon by polymerizing carboxylic acid and amide monomers to the surface of activated carbon,making the as-prepared modified activated carbon possess the strong adsorption capacity of carboxylic acid and amide functional groups to calcium and magnesium ions in water and the larger surface area of activated carbon to make up for the weak adsorption capacity of activated carbon to calcium and magnesium ions in water and the smaller specific surface area of carboxylic acid and amide resin.In this thesis,a kind of carboxylic acid and amide modified activated carbon P?MAA-AA-MBAA?@AC was prepared by in situ polymerization of acrylic acid,methyl acrylamide,and the crosslinking agent N,N-methylene diacrylamide and sodium hydroxide neutralization on the surface of activated carbon.Since the preparation of modified activated carbon is carried out in aqueous solution and the reaction conditions are mild,the use of a large number of organic solvents is avoided and the process is green and environmental friendly.The results showed that the adsorption capacity of P?MAA-AA-MBAA?@AC prepared under the optimized conditions for calcium and magnesium ions in water reached 41.2 mg/g,which is fifteen times of the adsorption capacity of unmodified activated carbon.The adsorption function regeneration test of P?MAA-AA-MBAA?@AC showed that after it saturatedly adsorbed calcium and magnesium ions in water its adsorption capacity for calcium and magnesium ions could reach almost 100%recovery via immersing it in the saturated salt water.The adsorption capacity of P?MAA-AA-MBAA?@AC for calcium and magnesium ions in water is almost not reduced after 5 consecutive saturated adsorption-salt water immersion.This showed that P?MAA-AA-MBAA?@AC could be reused many times and has a very long service life.