Synthesis Of Zeolite By Activated Attapulgite As Precursor And Research Of Hybrid Membranes

The major challenge of people facing that is the environmental problem in the 21st Century.With the sustainable development of society and the rapid increase of population,it is becoming more and more striking that the contradictions between water supply and demand.Meanwhile the shortage and the environmental pollution in the exploitation of petrochemical energy,how to effectively realize the regeneration of water resources and the clean utilization o f water treatment process,which has been become the common concern in the world.Separator material is the main component of microbial fuel cell(MFC),whose type and performance have great influence on the power generation capacity of MFC.It has important significance in water treatment and development of new energy.PVA based hybrid membranes improve their mechanical properties and structural stabilities with the framework sustain of zeolites.The perforated structure through the proton was formed by the regular pore channel of the zeolite,and the organic chain segm ents were modified by membrane modification and pore wall,while inhibiting the water absorbability and swellin,g of the membrane,the exchange group and proton conductivity of membrane can be enhanced by surface acidic sites and cation of the framework.The added zeolite is derived from the activation of attapulgite,the silicate clay.After the directional synthesis of zeolite,the properties of the hybrid membranes are studied,so as to provide effective ways for the low-cost,high-performance preparation of organic-inorganic hybrid membranes.The main contents and conclusions are as follows:(1)The framework,crystal structures and morphologies ofactivated attapulgite were firstly analysised.Results showed that alkali roasting activation can selectively replace the metal cations in the framework of palygorskite.Among of them,the content of Silicon increased in the products of ATP roasted by NaOH(NC-ATP),with K,Ca,Cu plasma of the framework re mo ved.Therefore,NaOH was selected for alkali activation of ATP in air atmosphere at high temperature.In the same structure as the molecular sieve and provides a precursor for its synthesis.(2)Three kinds of zeolites,ZSM-5,ZSM-12 and ZSM-11 molecular sieves were obtained,respectively,when HM-NC-ATP,HM-ATP and HH-ATP as the precursor and TEAOH as template,the species,structure and morphology of the products were affected on the ratio of Si to Al,the crystallization temperature,the crystallization time and the dosage of the template,and so on.Under the same crystallization conditions,the synthesized samples had significant difference between crystal structure and species,and the pore and specific surface area happen to change as well.The ratio of Si to A1 and the dosage of template played a certain role in the type and morphology of synthesised zeolite.(3)HH-NC-ATP and HM-NC-ATP were used as precursors to synthesize zeolites under the combined action of TPAOH and CTAB.Research found that the crystal growth origin from the solid nucleation in the process,then the precursor was continuously assembled under the action of TPAOH,and gradually crystallize ZSM-5 with a crystal surface.The pores structure inside the crystal transformed from the large holes to the micropores,and then formed the mesoporous micropores.The crystal particle is easy to form the accumulation by the overlong hydrothermal time,and blocking the inner pore of the particles,which resulted in the reduction of specific surface area.Under the combined action of TPAOH and CTAB,the amount of CTAB lead to the transformation from ZSM-5 to(H)ZSM-11 zeolite.SEM results showed the irregular changes in size and shape of zeolite,and the relative crystallinity is different.(4)The ATP,modified ATP,ZSM-5 and(H)ZSM-11 zeolite were doped to PVA membrane,and then formed the organic-inorganic hybrid membrane.The water absorption,swelling rate,ion exchange,proton conductivity and thermal stability of the hybrid membranes were tested.The crosslinking properties of PVA/NC-ATP/FA and PVA/HH-NC-ATP/FA membranes decreased significantly,while proton conductivity decreased.It indicated that the doping of three substances did not play an effective role in proton conduction.When the zeolite was added to the PVA/FA membrane,the hydrophilicity of hybrid membrane greatly improved.In liquid environment,it could inhibit the swelling caused by water molecules and retard the failure time of the membrane,meanwhile improved the ion exchange and proton conduction ability of the membrane.