牛粪及其蚓粪对Cu、Zn吸附特性的差异研究
时间:2020-07-03 16:52 来源:毕业论文 作者:毕业论文 点击:次
摘要:实验利用室内环境研究,分别采用牛粪及其蚓粪对Cu2+、Zn2+溶液等温吸附、解吸规律、不同pH对吸附的影响及吸附动力学行为的研究。结果表明,在试验浓度范围内,牛粪和蚓粪对 Cu2+、Zn2+的吸附量均跟随 Cu2+、Zn2+浓度的增加而增加,蚓粪对 Cu2+、Zn2+的吸附固定能力明显高于牛粪。牛粪和蚓粪对 Cu2+、Zn2+的吸附等温线与 Langmuir方程有较好的拟合性,与Freundlich方程的拟合性也不错。牛粪和蚓粪中 Cu2+、Zn2+的解吸量随着溶液的浓度增加而增加,在相同初始浓度条件下,牛粪吸附的 Cu2+更易被解吸,而牛粪和蚓粪对 Zn2+的解吸能力相近。蚓粪对 Cu2+、Zn2+的吸附速率高于牛粪,10-30 min 之内可以达到平衡后吸附总量的 80%以上;pH在7左右的时候吸附量最大。51953 Abstract: :Copper and zinc are the commonly-occurring micronutrients used in Cow dung since their anti-microbial and growth-stimulat-ing effects. As the end product of using earthworm to break down Cow dung, vermicompost has much larger surface area mainly because of the increased decomposition and humification during earthworm treatment period. Since both Cow dung and its vermicomposts are organic wastes and can be used as organic fertilizers for agricultural soils, they may have some different effects on the behaviour of the existed copper and zinc. In this paper, Cu2+and Zn2+ adsorption behaviour on Cow dung waste and its vermicompost were studied. The results showed that Cu2+, Zn2+ adsorption increased with the initial Cu2+, Zn2+ concentration and vermicompost had a much higher Cu2+ and Zn2+ adsorption capaci-ty than Cow dung. The adsorption isotherm of Cu2+, Zn2+ by the absorbent could significantly conform to Freundlich and Langmuir equations.Cu2+ and Zn2+ desorption by these two absorbent increased with their increasing adsorption amount. With the same initial concentration, it was easier for Cu2+ to release from pig manure than from vermicompost while it was nearly the same for Zn2+ desorption. The Cu2+, Zn2+ Adsorption on both Cow dung and its vermicompost were rapid reaction, and the adsorption rate of Cu2+, Zn2+ in vermicompost was much higher than that in Cow dung waste. with 80% of Cu2+, Zn2+adsorbed in the first 10~30 min and reached equilibrium quickly. pH around 7 is biggest adsorbed. 毕业论文关键词:牛粪;蚓粪;吸附;解吸;Cu;Zn Keywords: cow dung; vermicompost; adsorption; desorption; Cu; Zn 目 录 1.材料与方法6 1.1供试材料6 1.2研究方法6 1.2.1吸附实验··6 1.2.2 pH对吸附的影响实验···6 1.2.3吸附动力学实验6 1.2.4解吸实验··7 1.2.5计算方法··7 2.结果与分析 ···7 2.1牛粪及其蚓粪的吸附等温曲线··8 2.2溶液pH对Cu、Zn的吸附影响··9 2.3吸附动力学模型··10 2.4解吸模型11 3.结论·12 4.参考文献·13 5.致谢·14 由于工业化文明的加快,人口过度增长,增加了对水资源的需求。因此,废水需要经过净化和回收利用替代水源[1]。在各种处理技术,吸附是一种快速且通用的方法,它提供重要的优势,如低可用性,成本,盈利能力,效率和易操作[2]。如果牛粪及其蚓粪处理水中的重金属Cu、Zn的差异研究效果达到预期目标,那么这对于牛粪资源化利用提供另一个途径。 随着规模化、现代化、集约化养殖的发展,特别是在国家一系列支持大型家畜发展的政策扶持下,大大加快了牛养殖业的发展速度。然而大量的牛粪堆积造成严重的环境污染问题日益加剧,2013年全国牛存栏量为10,343.4万头,牛粪日排泄量高达400~500万t[3]。尤其是规模化牛场,如果缺乏充分有效的处理利用方式,牛粪的大量堆积带来的污染将严重影响牛场正常的生产和阻碍畜牧业的可持续发展[4]。近年来,中国养牛业尤其是奶牛业发展迅速,据资料显示,每头奶牛日产粪尿约 58.93 kg,每头肉牛日产粪尿约24.32 kg,是猪日产粪尿 4~9 倍多,远远超过鸡鸭的日产粪尿。牛作为反刍动物,饲料经反复消化后粪质细密,通气性差,含水量高,养分含量低,且碳氮比范围宽,所以牛粪的腐解速度慢[5]。这么多的牛粪产量影响这我们的环境,我们可以研究用牛粪及其蚓粪来处理废水中的重金属Cu、Zn,寻找一个新的资源利用空间。 (责任编辑:qin) |