农业工程学报2016，Vol.32Issue(24)：248-254,7.DOI:10.11975/j.issn.1002-6819.2016.24.033
棉秆与污泥共热解制备生物炭工艺优化及其结构与吸附性能
Process optimization of char prepared from co-pyrolysis of cotton stalk and sludge and analysis on its structure and adsorption capacity
摘要
Abstract
The production of sludge and cotton stalk arise along with the rapid development of China’s economy. Currently the most common methods for sludge and cotton stalk disposal are landfilling, incineration, and application in land in China. And incineration of cotton stalk may bring new air pollution problems; it may contaminate soils and ground water when sludge is used in land as fertilizer. Therefore, it is necessary to find an efficient way for the sludge and cotton stalk recycling. As alternative technology for the common sludge and cotton stalk treatment methods, the pyrolysis has been researched. But there are few researches on the effect of reaction conditions on surface structure properties of chars obtained from co-pyrolysis of sludge and biomass, as well as the research on the relationship between surface structure and adsorption properties. In this study, the pore structure properties (BET surface area, total pore volume and average pore width), the abundance of surface functional groups and the adsorption capacities of sludge and cotton stalk chars (SCA) were analyzed under 5 different reaction conditions. The reaction conditions included sludge content, concentration of KOH (potassium hydroxide) solution, radiation power, radiation time and loading amount. Chars were made from the mixtures of cotton stalk and sludge by microwave heating via KOH activation. The adsorption capacities of SCA were measured by removing methylene blue (MB), acid fuchsin (AF), iodine and copper sulphate (CuSO4) in aqueous solution. The correlations between the structure parameters and the adsorption capacities were calculated to test if the structure would affect the adsorption properties of chars. The results showed that all reaction conditions influenced the pore structure properties, and the abundance of surface chemical groups of chars significantly. On the same structure parameter, the effects of 5 conditions were not the same. For all pore or chemical structure parameters, each of these factors showed the influence with different capacities, and all the responses showed different trend with the change of condition levels. The adsorption capacity of SCA could reach the national stand of wooden activated carbon. All reaction conditions influenced the adsorption capacities to the MB and the CuSO4 significantly, but its influence on the adsorption capacities to AF and iodine was not significant. And for the same adsorption capacity, the reaction conditions showed different influence. The composite index, which was calculated by the adsorption capacity to MB, AF, iodine and CuSO4, was used to optimize the preparation process of the char, and the optimal parameters were as follows: the sludge content of 30%, the concentration of KOH solution of 50%, the radiation power of 280 W, the radiation time of 24 min and the loading amount of 150 g. The adsorption capacities of the SCA to MB, AF, iodine and CuSO4 obtained at the optimal parameters were 157.80, 293.39, 1281.93 and 272.12 mg/g, respectively. The effects of the reaction condition on composite index were as follows: load amount > radiation time > sludge content > radiation power > KOH concentration. The chemical and pore structure properties of the chars and the characteristics of the adsorbate influenced the adsorption properties of SCA significantly. The number of total acidic groups and total pore volume had significant correlation with the adsorption capacity to AF and CuSO4respectively. But other single structure characteristic did not significantly correlate with the adsorption capacity of SCA. The adsorption of SCA to the pollutants is not a single physical adsorption or chemical adsorption. The research results can provide a reference for designing an effective adsorbent made from the SCA.关键词
废弃物/污泥/生物质/棉秆炭/吸附性能/KOH活化-微波热解法/表面结构Key words
wastes/sludges/biomass/cotton stalk chars/adsorption capacity/potassium hydrate activation-microwave pyrolysis method/structure properties分类
资源环境引用本文复制引用
邓辉,李政家,金志文,张涛..棉秆与污泥共热解制备生物炭工艺优化及其结构与吸附性能[J].农业工程学报,2016,32(24):248-254,7.基金项目
国家自然科学基金项目（51368051与51162024）石河子大学高层次人才科研启动资金专项（RCZX201204）；石河子大学杰出青年项目（2012ZRKX JQ-05）。 （）
