Preparation And Properties Of Bamboo Nanocellulose/Montmorillonite Composite Adsorbent Materials

The expansion of industrial activities has resulted in to the release of large quantities of pollutants into aquatic system,such as organic dyes,heavy metals,etc.It is destroying the ecological environment and seriously threatening human health.Nanocellulose has a wide variety of sources,a large specific surface area,and a large number of hydroxyl groups,which has a good adsorption potential.Montmorillonite is often used as an adsorbent because of its low cost and cation exchange capacity.Therefore,bamboo nanocellulose/montmorillonite composite adsorbent materials were prepared from bamboo nanocellulose and montmorillonite,and the adsorption behaviour and mechanism of the two composites on cationic pollutants were explored.The main findings are as follows:(1)Study on the preparation and adsorption properties of bamboo nanocellulose/montmorillonite/polyethyleneimine compositeWaste bamboo fiber paper and montmorillonite were used as raw materials.Carboxylated bamboo nanocellulose was prepared by TEMPO oxidation method,and montmorillonite was reduced to two-dimensional montmorillonite nanosheets by ultrasonic stripping in order to expose adsorption active sites,Then,polyethyleneimine(PEI)with rich amino groups was used as a cross-linking agent to reinforce the connection between bamboo nanocellulose and montmorillonite nanosheets for producing a stable aerogel adsorbent(BMP),which was used as an adsorbent to remove the cationic dye,MB,and Cu(Ⅱ)in aqueous solutions.The maximum adsorption capacities of MB and Cu(Ⅱ)were found to be 361.9 mg/g and 254.6 mg/g,respectively.After five cycles,the removal rates of MB and Cu(Ⅱ)were maintained at 49.3% and 47.1%,respectively.These results indicated that the adsorbent material had a great potential for the removal of MB and Cu(Ⅱ)from aqueous solutions.(2)Study on the preparation and adsorption properties of bamboo nanocellulose/montmorillonite magnetic compositeIn order to selectively adsorb and recover organic dyes from complex wastewater,a new type of magnetic adsorption material(BAMM)was prepared by mixing acrylic modified bamboo nanocellulose with magnetic modified montmorillonite nanosheets.The vibrating sample magnetometer(VSM)result showed that the magnetic adsorbent had a paramagnetic property,so that it was easy to be recovered by magnets.The adsorption experiments indicated that the BAMM showed a prominent adsorption ability toward MG over a wide range of pH.More interestingly,MG could be selectively adsorbed and separated by BAMM from complex wastewaters(such as a mixed dye solution of MG/MO,aqueous solution with high salinity,and real river samples).The maximum adsorption capacity of the material for MG was calculated to be 2282.3 mg/g,which was remarkably higher than other works.According to the thermodynamic study results,the adsorption process for MG was spontaneous and endothermic.After 5 cycles,the adsorbent was able to remove above 53.4% of MG.Therefore,BAMM had a strong adsorption performance,excellent selectivity,and recyclability,which could be used for selective adsorption and separation of MG in complex wastewater...