Study On The Enhancement And Sorption Properties Of Cellulose Based Aerogels

The oil spills and industrial wastewater have brought serious pollution and destruction to our environment,and they also pose a great threat to human health.Sorption is one of the most important methods for water pollution.An ideal sorbent is expected to possess advantages of low cost,green,high absorption capacity and excellent reusability.The sorbent used in the field of oil-water separation should also have high oil/water selectivity.Cellulose-based aerogels with abundant cellulose as the main raw material was often used as sorbent for water pollution because of the advantages of rapid sorption,high sorption capacity,environment-friendly and low cost.In this work,cellulose aerogel exhibited unique advantages in the field of sorption through modification and compounding other materials.For example,the cellulose based aerogel of chitosan-oxidized cellulose aerogel prepared in this work have excellent reusability in dealing with water environmental pollution caused by oil spills.In dealing with the water pollution caused by heavy metal ions,the cellulose based aerogel of waste paper-chitosan aerogel obtained in this work have high adsorption capacity for heavy metal ions,and this method effectively converts waste office paper into valuable material.The contents and results of this research are as follows.A new kind of cellulose-based aerogel was successfully fabricated via cellulose oxidation,crosslinking with chitosan,and the freeze drying technique.This preparation made chitosan crosslink with cellulose chains.The chemical crosslinking endowed aerogel with better resilience,which will help to keep a good structural integrity and improve reusability.Orthogonal test showed that the best experimental conditions for the preparation of chitosan-oxidized cellulose aerogel were:3 wt%cellulose,54.2%aldehyde content,0.5 wt%chitosan solution and reaction time for 12 h.This chitosan-oxidized cellulose aerogel still had high adsorption capacity after 50 cycles of compression,which has a great improvement compared with the pure cellulose aerogel.In order to improve the oil-water selectivity of chitosan-oxidized cellulose aerogel,TMCS was used as modifier to modify the aerogel by cold plasma modification.The aerogel,with a water contact angle up to 152.8°,exhibited hydrophobic ability after modification.This hydrophobic aerogel possessed high absorption capacity for non-polar liquids such as oils and organic solvents,but hardly absorbed water,showing high oil-water selectivity.Waste paper,without deinking and bleaching,was used as the source of cellulose in this study.Combining waste office paper and chitosan,the aerogel obtained the enhanced mechanical strength,acid resistance and high adsorption capacity(up to 156.3 mg/g for Cu2+).This adsorption process obeyed the pseudo-second order model and the Langmuir model.Adsorption mechanism showed that a coordination compound was formed between amino group and Cu2+ during the adsorption process.The adsorbent could be regenerated well in 0.1 M H2SO4 with up to 98.3%desorption efficiency.