摘要在镀镍污水中,总磷是其中主要的污染物,去除的方法有多种,根据其所运行的机理,总而言之大致上可分为化学沉淀除磷和生物除磷两种方法。
使用生物除磷法虽然成本低但效果却不稳定,并且部分传统方法根本不具备生物除磷的能力。化学沉淀除磷法效果稳定,但是运行成本较高、污泥量较大,企业负担较重。
在诸多不利条件下,鉴于此,为实现控制除磷效果的目的,本论文提出使用低成本的药剂,对各个与之相关因素进行研究,主要是对反应物浓度配比,反应时间,沉淀的最佳PH值等相关因素进行研究,力求最佳的除磷方法。切实有效的解决目前化学镀镍生产中排放废水磷超标的难题。41195
本文选择了化学镀镍废液与综合废水二沉池的废水做了研究。首先,以化学镀镍废液为对象,研究重金属捕捉剂(N,N-二甲基氨基二硫代甲酸钠)对废液中镍的去除能力。试验结果表明,N,N-二甲基氨基二硫代甲酸钠(又称福美钠)对镍离子的螯合能力大于化学镀液中的所有络合剂,可以完全将镍离子从原络合物中螯合沉淀。在经过足量的福美钠处理后,镍离子浓度可从原来的4-5g/L降低到0.1ppm以下。且所生成的螯合沉淀物颗粒极大,镍含量高,具有很高的回收价值。
根据研究分析表明,当直接采用化学沉淀方法时,由于废液里所含有的未氧化的次磷酸盐以及络合剂能够极大地影响了亚磷酸盐、正磷酸盐的沉淀 ,结果导致总磷不完全去除,去除的效率仅仅只有30%。
对除镍之后的废液进行氧化破络之后除磷,研究改变反应浓度、氧化剂的种类、反应所需时间、沉淀pH值的影响。此时废液除磷率可以达到80%-90%,综合废水二沉池总磷含量可以降低到0.5ppM。对比未采用此方法前,总磷去除率分别提高了35.94%与40.37%。
最后,研究了在极端条件下的废水去除总磷效果,试验了在低pH值、高pH值、低温下,对于总磷去除效果的影响。
毕业论文关键词:化学镀镍;废液;磷
Abstract
In nickel plating sewage, the total phosphorus is one of the main pollutants; there are many methods to remove. According to the mechanism of its operation, generally they can be broadly pided into two removal methods, which is chemical deposition dephosphorization and biological dephosphorization respectively.
The cost of using the biological dephosphorization method is low while the effect is unstable, and part of the traditional methods does not have the ability of biological dephosphorization. Although the effect of chemical deposition dephosphorization method is stable, enterprises have relatively heavy burden on high operation cost and large quantity of sludge.
In many adverse conditions, in view of this, in order to achieve the purpose of the control of phosphorus dephosphorization effect, this paper puts forward using low cost of reagents, at the same time we do some research on various related factors, we study the mainly related factors on the concentration ratio of reactants, reaction time, the best of pH value of precipitation to strive to make the best of phosphorus dephosphorization methods. Practical and effective to resolve the discharge wastewater phosphorus levels in the chemical plating nickel production problems.
This article chose the chemical nickel plating liquid waste and comprehensive wastewater secondary settling tank wastewater to do the research. First of all, we take with chemical nickel plating liquid waste as an object, we research the denickel ability of heavy metal capturing agent (N, N- dimethyl dithiocarbamate sodium). The results showed that the chelating ability of nickel ions of N, N- dimethyl dithiocarbamate sodium (also known as Fuk US sodium) is greater than all the complexing agent in the chemical plating solution, which can completely chelate nickel ions precipitate from the original complex. After a sufficient proportion of the sodium treatment, nickel ion concentration can be reduced from the original 4 -5 g/L to under 0.1 parts per million. And the resulting chelating sediment particles are great, which has high nickel content and the very high collection value.
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