本文選題：CMC　切入點：FeS納米粒子　出處：《太原科技大學》2015年碩士論文

【摘要】：鎘是自然界中普遍存在的一種劇毒金屬元素,可以通過各種地質(zhì)因素和人為活動等方式釋放到環(huán)境中,造成土壤、大氣、水體中鎘含量超標。鎘污染土壤的修復(fù)和安全利用已成為國內(nèi)外的研究熱點。有關(guān)研究發(fā)現(xiàn)硫化亞鐵(FeS)可以有效的處理土壤和地下水中的重金屬。它來源廣泛,呈無定形態(tài),比表面積大,處理效率高,本文利用FeS作為鈍化劑來吸附土壤和地下水中的重金屬鎘,主要做了以下方面的工作:采用綠色無污染的有機聚合物羧甲基纖維素鈉(CMC)作為穩(wěn)定劑制備FeS納米粒子,并將它用于土壤和水中重金屬鎘的去除,考慮FeS的量、粒徑大小、腐殖酸、常見陰離子等對吸附的影響,結(jié)果表明:1、CMC可以使合成的FeS納米粒子穩(wěn)定分散,FeS納米粒子能夠長期均勻穩(wěn)定的分散在一定量的CMC水溶液中,不發(fā)生沉淀、團聚;2、當CMC和FeS的摩爾比為0.0010時,CMC-FeS對水中鎘的去除效率為87%,吸附過程符合準二級吸附動力學速率方程,吸附等溫線與Freundlich模型吻合;3、FeS納米粒子的粒徑隨著CMC量的增加而減小,納米粒子的分散穩(wěn)定性逐漸增強,但粒子之間的流動性會降低;隨著CMC和FeS的摩爾比不斷增大,FeS納米粒子吸附Cd的效率增高,當CMC和FeS摩爾比為0.0010時,FeS納米粒子吸附Cd的效率達到最高值;當CMC和FeS摩爾比再繼續(xù)增大時,FeS納米粒子吸附Cd的效率反而下降;4、腐殖酸可以增強FeS納米粒子對水中鎘的修復(fù)。當腐殖酸加入0.13g/L和0.40g/L時,FeS顆粒對水中鎘的吸附率分別達到95%和97%;5、FeS可以增大土壤中難溶態(tài)Cd的量。FeS納米粒子濃度分別為0g/L、0.05g/L、0.1g/L、0.2g/L、0.5g/L時,土壤中鎘的解吸量分別為63.55μg/L、29.525μg/L、4.54μg/L、0.5075μg/L和0.1135μg/L;與空白實驗相比,土壤中難溶態(tài)Cd的量分別增加了53.5%、92.9%、99.2%和99.8%;6、有機酸和無機陰離子的加入對FeS固定土壤中的鎘的影響很大。甲酸、酒石酸和檸檬酸可以增大土壤中難溶態(tài)Cd的量,隨著甲酸、酒石酸和檸檬酸濃度的增大,FeS土壤中難溶態(tài)Cd的量增大;硫酸根和磷酸二氫根也增大了CMC-FeS對土壤中Cd的固定量。隨著硫酸根和磷酸二氫根的濃度增大,土壤中難溶態(tài)Cd的量增加;隨著硒酸根濃度的增大,CMC-FeS對土壤中Cd的解吸量增大。
[Abstract]:Cadmium is a highly toxic metal element widely existing in nature, which can be released into the environment by various geological factors and human activities, resulting in excessive cadmium content in soil, atmosphere and water body.The remediation and safe utilization of cadmium contaminated soil have become a hot spot at home and abroad.It is found that ferrous sulfide can effectively treat heavy metals in soil and groundwater.In this paper, FeS was used as passivating agent to adsorb heavy metal cadmium in soil and groundwater.The main work of this paper is as follows: FeS nanoparticles were prepared by using green organic polymer, carboxymethyl cellulose sodium, as stabilizer, and used to remove heavy metal cadmium in soil and water, considering the amount and size of FeS.The effects of humic acid and common anions on the adsorption showed that the synthesized FeS nanoparticles could be dispersed steadily and steadily in a certain amount of CMC aqueous solution for a long time without precipitation.When the molar ratio of CMC and FeS is 0.0010, the removal efficiency of CMC-FeS in water is 87. The adsorption process accords with the quasi-second-order adsorption kinetic rate equation, and the particle size of FeS nanoparticles decreases with the increase of CMC content, and the adsorption isotherm coincides with the Freundlich model.The dispersion stability of nanoparticles gradually increased, but the fluidity between particles decreased, and with the increasing of molar ratio of CMC and FeS, the efficiency of CD adsorption by FES nanoparticles increased.When the molar ratio of CMC to FeS is 0.0010, the adsorption efficiency of FES nanoparticles reaches the highest value, and when the molar ratio of CMC and FeS continues to increase, the adsorption efficiency of FES nanoparticles decreases by 4%. Humic acid can enhance the repair of cadmium in water by FeS nanoparticles.褰撹厫孌栭吀鍔犲叆0.13g/L鍜，

本文編號：1705011