摘要
以市政污泥为原料,在300、500和700℃无氧气氛下热解制备污泥基生物炭,探讨不同热解温度对污泥基生物炭性质的影响,研究污泥基生物炭对水溶液中重金属Cd^(2+)的吸附特性。结果表明,随着热解温度升高,污泥基生物炭的产率降低,pH值增大,碳、氢、氧和氮含量降低,芳香化程度增强,亲水性和极性降低,稳定性增强;随热解温度的升高,比表面积不断增大,生物炭表面变得粗糙并且出现明显的孔隙,但平均孔径呈现先增大后减小。在700℃下制备的污泥基生物炭对水溶液中Cd^(2+)的吸附效果优于其他制备温度下获得的生物炭,温度为298.15 K时,最大吸附容量为27.47 mg·g^(-1)。污泥基生物炭对Cd^(2+)的吸附动力学符合准二级动力学方程模型,吸附速率主要由化学吸附控制。污泥基生物炭对Cd^(2+)的吸附表现为快速吸附过程,生物炭前10 min的吸附量超过饱和吸附量的80%。Langmuir吸附等温模型能很好的描述污泥基生物炭对Cd^(2+)的吸附行为,吸附容量随热解温度升高而增大。
Biochar was derived from municipal sewage sludge at three different temperatures （300,500, and 700 ℃ ） in an oxygen-poor environment. The objectives were to explore the influence of different pyrolysis tem- peratures on the properties of the sludge biochar,and to study the adsorption of aqueous Cd^2＋ by the sludge bio- char. The results showed that, with increase of the pyrolysis temperature, the yield ratio of sludge biochar decreased;the pH and degree of aromatization increased;the C, H, N, and O content decreased;the hydrophilic character and polarity decreased;and the stability of the sludge biochar increased. Meanwhile,the specific sur- face area of the sludge biochar increased and its surface became very rough and appeared porous. The average pore diameter first increased ;then decreased,with increasing temperature. The capability for sorption of Cd^2＋ by the sludge biochar made at the pyrolysis temperature of 700 ℃ was better than at other preparation temperatures. The maximum adsorption capacity of the sludge biochar made at 700 ℃ was 27.47 mg · g^-1 The sorption of Cd^2＋ on sludge biochar followed the pseudo-second order dynamic sorption model, and the adsorption rate was mainly controlled by chemical adsorption. The sorption of Cd^2＋ on the sludge biochar showed a rapid adsorption process ; the adsorption of the sludge biochar in the first ten minutes was 〉 80% of its maximum capacity. The i- sotherm sorption behavior was described by the Langmuir model,and the sorption capacity of the sludge biochar increased with increase in the pyrolysis temperature.
出处
《环境工程学报》
CAS
CSCD
北大核心
2017年第7期4029-4035,共7页
Chinese Journal of Environmental Engineering
基金
国家自然科学基金资助项目(31560234)
兰州市科技计划项目(2014-1-189)
甘肃省自然科学基金资助项目(1506RJZA077)
甘肃省高等学校科研项目(2014B-038)
兰州交通大学青年科学基金项目(2013014)
关键词
市政污泥
生物炭
温度
吸附
CD^2+
municipal sewage sludge
biochar
temperature
adsorption
Cd^2＋
