Preparation Of Porous Titanium Dioxide Microspheres And Their Application In Dye Wastewater

The pollution of printing and dyeing wastewater is an important factor restricting the sustainable development of textile industry.Electrochemical method,biological oxidation method and adsorption method are commonly used to treat dye wastewater,among which adsorption method has attracted much attention because of its advantages of simple operation,low equipment requirements,low cost and wide adaptability.Developing new adsorbents is an important starting point to promote the treatment of printing and dyeing wastewater by adsorption.In this study,porous titanium dioxide（Ti O₂）microspheres were prepared by hydrothermal method,and the ionic dyes in dye wastewater were treated with Ti O₂ microsphere powder and Ti O₂microsphere/nonwoven composite as adsorbent/adsorption medium respectively.The research results provide theoretical support and practical basis for efficient treatment of dye wastewater.The research contents of this paper mainly include the following three aspects:（1）Preparation and properties of porous Ti O₂ microspheres.The influence of synthesis parameters on the morphology and structure of microspheres was investigated.The surface morphology,particle size distribution,crystal form,structural components and surface potential of microspheres were systematically analyzed.（2）Study on the application of porous Ti O₂ microspheres in ionic dyes.The adsorption properties of porous Ti O₂ microspheres were improved by optimizing adsorption conditions;Based on the photocatalytic degradation ability of porous Ti O₂ microspheres,the reusability of porous Ti O₂ microspheres was analyzed and evaluated（3）Preparation and application of composite materials based on porous Ti O₂ microspheres.The influence of preparation conditions on the adsorption effect of the composite was analyzed,and the surface morphology,element composition and hydrophilicity of the composite were characterized.The load fastness of Ti O₂ microspheres was analyzed by water washing test.To evaluate the dye adsorption and reuse performance of Ti O₂microspheres/nonwoven composites.The results show that:（1）Porous spherical Ti O₂ was successfully prepared by hydrothermal method.The addition of titanium source,surfactant and reaction temperature will obviously affect the morphology and structure of the product.The reaction must be carried out under alkaline conditions and rapid stirring;The surface of porous Ti O₂ microspheres contains a lot of hydroxyl groups,and its crystal form is anatase.The surface of porous Ti O₂ microspheres（G-Ti O₂）prepared by adding cetyltrimethyl ammonium bromide（CTAB）is positively charged,while the surface of porous Ti O₂ microspheres（Y-Ti O₂）prepared by adding sodium dodecyl sulfate（SDS）is negatively charged.（2）G-Ti O₂ can only adsorb Congo red dye and Y-Ti O₂ can only adsorb methylene blue dye;When ionic dyes coexist with other ions of the same sex,it will affect the adsorption of dyes by porous Ti O₂ microspheres to some extent.The results of adsorption kinetics analysis show that it conforms to the quasi-second-order kinetic model and the adsorption isotherm conforms to Langmuir model.The performance of G-Ti O₂ and Y-Ti O₂ adsorbents is seriously affected by the loss of powder after five cycles.（3）The composite material was prepared by using PDA as adhesive,and PDA was successfully polymerized on the fiber surface,which improved the hydrophilicity of the carrier;The addition of PDA improves the adhesion of porous Ti O₂ microspheres to non-woven fabrics;The properties are highly related to the concentration and loading time of porous Ti O₂ microspheres dispersion used in preparation.After five times of recycling,it still has good dye adsorption ability.