Studies On Preparation Of Cellulose-based Carbon Aerogels And Its Adsorption Property

Recent years,with the development of modern industry and agriculture,a variety of metal ions and organic wastes have been discharged into rivers,streams and lakes,causing serious pollution problems in these water source,which depended by human being and biological species.Adsorption is an efficient technology for removing metal ions and organic pollution from water.The development of novel,efficient,and environmentally friend adsorbents is the key for application of this technology in water treatment.As a novel kind of porous carbon materials,carbon aerogels based on cellulose have many obvious advantages as high performance absorbent material used in environmental remediation,such as high porosity,low cost,large surface area,and strong adsorption,implying their potential application in water treatment.In this thesis,micro-crystal cellulose was selected as precursor for preparation of the novel carbon aerogels through cellulose sol-gel reaction,freezing-dry,and carbonization;the properties and mechanisms of adsorption on the prepared carbon aerogel in water solution are also systemically discussed.The main results are listed as following:(1)Cellulose-based carbon aerogel with network pore and surface group of hydroxyl was prepared from cellulose colloid.Surfactant like isooctyl alcohol ether phosphate was added in sol-gel reaction of cellulose,for construction of porous network in the prepared samples.The properties of CCAx prepared with Oep-70 modification are much better than those without Oep-70 modification,for adsorption of copper ions in the water solution.The prepared carbon aerogel of CCA2 has a maximum capacity about 55.25 mg/g for Cu2+ in neutral aqueous solution.It is also found in adsorption process the kinetics nicely follows pseudo-second-ord-er rate expression,and the isotherm fits Langmuir model.(2)Cellulose-based carbon aerogels with well-developed porous structure was synthesized from cellulose colloid,with phosphate of polyoxyethylene isooctyl ether(AEP)as structure inducer.The adsorption of copper ion in aqueous solution was investigated through a static adsorption method.Results showed that AEP can obviously regulate the porous structure of the prepared samples and improve their adsorption properties.The maximum copper ions adsorption capacities were 86.27 mg/g obtained from the prepared carbon aerogel of CCP2.It is also found in adsorption process the kinetics nicely follows pseudo-second-order rate expression,and the isotherm fits Langmuir model.(3)Cellulos-based carbon aerogel with specific pore structure was synthesized from sol-gel reaction of cellulose with phenol-formaldehyde resin(PF)as molecular binder.Results showed that the PF obviously regulated the microstrctural morphology of the prepared samples.The prepared carbon aerogel of CCF0.5 obtained with a high carbon yield of 45%and well-formed pore network,characteristic of a specific area about 1426.11m2/g and total pore volume about 1.14 cm3/g,exhibits remarkable performance as adsorbent for removing methylene blue(MB)in aqueous solution.In an aqueous solution with 100 mg/L of MB and pH of 7.0,the MB removal ratio of CCF0.5 can reach 99%within 10 min under 25?;and the maximum adsorption capacity of CCF0.5 taking MB is about 501.26 mg/g in neutral solution,It has been also found in adsorption of MB on the prepared carbon aerogel,the isotherm fits Langmuir model and the kinetics follows pseudo-second-order model.