Study For The Degradation Of Phenol By CuO/ Biological Activated Carbon Fibers Catalyst

Biological template method is a new technology developed in recent years for preparing nano materials. The method is that the nano structures of inartificial biological materials are used as the templates and the target materials can be formed through two steps of impregnation in precursor and air calcination. The target materials prepared by this technology are always single oxides without the remaining of carbon element in the templates. However, the biological activated carbon exhibits excellent properties of physical adsorption, which can be employed widely in many fields especially for the catalytic applications.In the relative investigations before, the carbon element in the bio-template has not been utilized adequately. Aiming to this problem, the study to obtain the composite materials of CuO/ activated carbon fibers is performed in this thesis. Because CuO is an excellent catalyst for phenol degradation, and biological activated carbon fibers possess superior properties of physical adsorption due to their unique structure with pore channels. Proceed from the composite effect, the biological activated carbon fibers loading with CuO catalyst can effectively catalyze the degradation of phenol and other organic matters in sewage.As a basic study, natural plant kapok fiber with a typical structure is chosen as the template materialin this thesis. The biological activated carbon fibers with high surface area and good morphology are prepared through the process of carbonization and activation for kapok fiber. And the composite materials retaining the original biological template form are fabricated by impregnating the template in metal salt solution and the process of sintering under atmosphere protection.A simple process route for preparing composite catalyst of biological activated carbon supported oxide through biological templates is attempted in this thesis. With copper nitrate solution as the precursor solution and kapok as the template, the optimum preparing conditions for activated carbon fibers are determined and the effect of experimental conditions on the synthesized target materials is studied. Through the exploration for experimental process, the reasonable control for the morphology of the target material is achieved. As a result, the target material CuO/ activated carbon fibers are prepared successfully and their catalytic properties are characterized.In this thesis, the effect of physical and chemical activation methods on the structures and properties of kapok based biological activated carbon fiber (kapok-ACFs) is studied. CuO/ACF composite catalyst is prepared and the characters on structure and mophology as well as the adsorption and degradation to phenol of catalyst with different CuO contents are analyzied. Energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), Raman spectroscopy, X-ray diffraction (XRD), infrared (FTIR), and nitrogen adsorption-desorption test method are adopted for the analysis and characterization on structure of materials. Methylene blue adsorption and phenol degradation test are utilized to characterize the properties of materials.The main conclusions are as follows:1. Using the kapok fiber as a template, kapok-ACFs are successfully prepared through carbonization and activation for template. For fabricating kapok-ACFs with high specific surface, the best carbonization temperature is 850℃, activation temperature is 1000, ventilation of activator CO₂ is 20 ml/min and activation time is 2h. Under this preparing process, the obtained kapok-ACFs show the largest specific surface of 1400 m2/g.2. Employing different concentrations of KOH, NaOH and ZnCl₂ for the activators, the kapok-ACFs are prepared and their structures and morphologies are analyzed. The results show that the kapok-ACFs activating by KOH of 10% and 40%as well as NaOH of 40% possess larger specific surface.3. With biological activated carbon fiber (kapok-ACFs) as a template, through immersing of the template in the copper nitrate solution, drying and calcination in nitrogen atmophere, CuO/ACF composite catalyst is obtained. The immersing time of 24 h, activated carbon fibers and CuO mass ratio of 1:1 and 1:9, and calcination temperature of 350℃in nitrogen are adopted as the process parameters for preparing CuO/ACF composite catalyst.4. The CuO /ACF composite catalyst with different CuO contents are used to the degradation of phenol. The catalytic results show that sample with activated carbon fiber and CuO mass ratio of 1:1 exhibits faster physical adsorption while that with activated carbon fibers and CuO mass ratio of 1:9 shows stronger degradation capability to phenol. This phenomenon is due to the higher content of the activated carbon fiber in the former which result in that the physical adsorption of activated carbon fibers is dominate in the reaction between CuO/ACF and phenol. However, the activated carbon fibers attached by a large number of CuO shows reducing content of the pore, and possess a slower physical adsorption rate while a stronger ability of the catalytic degradation.