Study On Synthesis Of The Porous Crosslinked Chitosan Adsorbent And The Adsorption Performance

Industrial wastewater containing dye, heavy metal ion or phenol do great harm to people’s health and the environment, and is becoming a huge challenge that people have to face. On the basis of previous studies, the natural polymer chitosan was used as matrix in this study to prepare porous crosslinked chitosan through pore-making, crosslinking, grafting, etc. Characterization and adsorption properties were also studied. Preparation conditions, effects of the static adsorption conditions on the adsorption of dye were discussed. Adsorption mechanism of heavy metal ions and phenol on the adsorbents were studied. The study provides certain theoretical basis and technical support for the treatment of industrial wastewater.Chitosan was used to prepare porous crosslinked chitosan by acid treatment, with ethanol as pore-making agent, formaldehyde as pre-crosslinking agent, epoxy chloropropane as crosslinking agent. The preparation conditions and the conditions of dye adsorption were studied. Results show that the adsorption of methylene blue and acid scarlet on the adsorbent both fit the Langmuir equation better; the adsorption process is endothermic process. Adsorption kinetics fits pseudo-secondary kinetics model, and the activation energy in the process is less than 41.9 k J/mol. The adsorption of methylene blue is mainly physical adsorption process, while the adsorption of acid scarlet is a chemical one. Study on the characterization show that the adsorbent has multi-porous structure; the specific surface area is higher than that of chitosan; epoxy chloropropane was crosslinked successfully to chitosan; the adsorbent can be reused four times without obviously adsorption capacity decline.Chitosan was used to prepare porous crosslinked chitosan, with polyethylene glycol(PEG) 2000 as pore-making agent, formaldehyde as pre-crosslinking agent, epoxy chloropropane as crosslinking agent, and triethylene tetramine as grafting agent. The preparation conditions and the adsorption conditions of Pb2+ and Au3+ were studied. The adsorption mechanism was also studied. Results show that there are more porous on the surface of the adsorbent; the specific surface area is higher; epoxy chloropropane was crosslinked on the group of amino and hydroxyl, triethylene tetramine was grafted on the crosslinked chitosan. The adsorption of Pb2+ and Au3+ on the sorbent fit the Langmuir equation better; the adsorption of Pb2+ and Au3+ are endothermic and exothermic process separately. Adsorption kinetics fit pseudo-secondary kinetics model. The adsorption is mainly chemical adsorption. The sorbent can be reused five times without too much adsorption capacity decline.Porous crosslinked chitosan adsorbent was prepared, with chitosan as raw materials, anhydrous ethanol as pore-making agent, formaldehyde as pre-crosslinking agent, epoxy chloropropane as crosslinking agent, and ethylenediamine as grafting agent. Preparation conditions and effect of adsorption conditions on the adsorption capacity. Results show that the surface of the adsorbent forms some holes and pores; specific surface area is higher than unmodified chitosan. Crosslinking were performed on the group of amino and generates the Schiff’s base. Adsorption process fits Freundlich equation well. The adsorption is an endothermic process. Adsorption kinetics fits pseudo-secondary kinetics model. The adsorption activation energy is less than 41.9 k J/mol. The adsorption can be operated under room temperature and can be well reused.