| Dyeing is an important and indispensable process in the textile industry.Firstly,fibers are dyed and spun into yarns of various colors to obtain fabrics with striped patterns,or fabrics made up of native sand threads are dyed to give them rich colors.However,the dyeing process is limited by the dyeing mechanism,and the dye molecules cannot be completely absorbed by the fibers during the dyeing process.Since China is the world’s largest producer and consumer of fiber,such residual dyes will firstly pose a great danger to the safety of our drinking water.Secondly,the majority of synthetic dyes have stable molecular structures and are not easily degradable,posing a long-term potential hazard to the natural environment.In this paper,we prepared a cellulose/nano-Ti O2 composite powder for the feature that most of the dyes used in dyeing（such as reactive dyes,acid dyes,direct dyes,etc.）are anionic,which forms a composite structure with the surface modified by molecular-level cellulose and nano-Ti O2 particles loaded on the surface of micron-level cellulose particles,and this structure is extremely conducive to the adsorption of anionic dye molecules in wastewater.This structure is highly conducive to the adsorption of anionic dye molecules in wastewater,with fast adsorption efficiency（<30S）and reusability after irradiation by xenon lamp（simulated sunlight）.Therefore,the systematic study of the preparation of this composite powder,the adsorption mechanism of dyestuff,the applicable environmental conditions and its reusability mechanism is of great theoretical significance and practical guidance to obtain a safe,feasible and practical dyeing wastewater treatment technology.Most importantly,the functional powder studied in this paper is capable of both adsorption in the physical method and reuse by post-process xenon light irradiation（chemical method）for color purification of dyeing wastewater,which is not available in other similar methods.Firstly,the cellulose/nano-Ti O2 composite powder was prepared by sol-gel method under certain conditions using cellulose powder and butyl titanate as raw materials,and the morphological structure and physicochemical properties of the cellulose/nano-Ti O2 composite powder were investigated.The results showed that the nano-Ti O2 formed in the composite powder was an anatase titanium dioxide with high catalytic activity in the exposed surface（010）.At the same time,the dissolved cellulose small molecule chains in the reaction system were successfully compounded with the nano-Ti O2 on the surface of the material through the action of ether and hydrogen bonds,and the positively charged cellulose/nano-Ti O2 composite powder with the three-layer composite structure of cellulose-Ti O2-cellulose was prepared.Secondly,the adsorption effect of cellulose/nano-Ti O2 composite powders on different anionic dyes was investigated under different environmental conditions.It was found that the adsorption efficiency of cellulose/nano-Ti O2 composite powder was close to 100%for reactive blue 49,acid red 73 and direct red FR within 30 S,and its high efficiency is in the leading position in the industry.Moreover,the adsorption efficiency of cellulose/nano-Ti O2 composite powder did not decrease significantly under different temperature and p H（except p H=12）,which is a kind of highly efficient adsorbent with high adaptability.Finally,the repeatable adsorption performance of the cellulose/nano-Ti O2 composite powder was systematically investigated using reactive blue 49 as a representative dye.The experimental results showed that under the combined effect of physical adsorption and chemical degradation,the adsorption efficiency of the cellulose/nano-Ti O2 composite powder could still reach 72%after seven times of repeated adsorption of the reactive blue 49 dye under xenon lamp（simulated sunlight）.This indicates that the prepared cellulose/nano-Ti O2 composite powder has excellent reusable performance and high social practical value in the field of dyeing wastewater treatment. |
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