Optimization of atrazine and imidacloprid removal from water using biochars: Designing single or multi-staged batch adsorption systems
Optimization of atrazine and imidacloprid removal from water using biochars: Designing single or multi-staged batch adsorption systems
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DOI：
10.1016/j.ijheh.2017.02.010
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发表时间：
2017-05-01
影响因子：
6
通讯作者：
Singh, Neera
中科院分区：
文献类型：
--
作者：
Mandal, Abhishek;Singh, Neera
背景：农业径流和工业排放产生的农药对地表水和地下水的污染是世界范围内水体污染的主要原因之一。生物炭是生物质热解和碳化后产生的高度芳香物质，对农药具有良好的吸附能力，可用于开发现场生物净化系统去除污染水体中的有机污染物。然而，单级间歇吸附装置需要大量的吸附剂，增加了水处理的成本；因此，对多级装置系统进行了研究。方法：评价了正常(RSBC)和磷酸处理(T-RSBC)稻草生物炭对阿特拉津和吡虫啉的吸附，数据符合Freundlich等温式。结果：两种生物炭对吡虫啉和阿特拉津均表现出较高的吸附容量。利用Freundlich吸附参数进行的模型研究表明，在单级、二级和三级吸附装置模型中，对于阿特拉津的95%的去除(10 mg/L)，RSBC和T-RSBC的用量(kg/1000 L)分别为8.84、2.44、1.61 kg和4.47、1.42、0.98 kg。对95%的吡虫啉脱除量(10 mg/L)分别为3.97、1.22、0.84 kg和3.98、1.38、0.96 kg。因此，两阶段模型建议比单阶段模型减少65-72%的吸附剂用量，而三阶段模型建议比两阶段工厂模型节省30%-34%的吸附剂。使用T-RSBC验证了单级和两级吸附装置模型的结果对阿特拉津的去除。结论：生物炭可以作为低成本的吸附剂去除污水中的阿特拉津和吡虫啉，可用于开发基于多批吸附系统的低成本吸附装置来去除这些农药。两级吸附装置模型的推广使用将大大降低处理过程的成本，特别是在农药浓度方面。
Background: Contamination of surface and ground water by pesticides from agricultural runoff and industrial discharge is one of the main causes of aqueous contaminations world over. Biochar, agricultural waste derived highly aromatic substance produced after pyrolysis and carbonification of biomass have exhibited good adsorption capacity for pesticides and can be used to develop on-site bio-purification systems for organic contaminant removal from polluted waters. However, high amounts of adsorbent required in single stage-batch sorption plant increases the cost of water treatment; therefore, multistage plant systems were investigated.Methods: Normal (RSBC) and phosphoric acid treated (T-RSBC) rice straw biochars were evaluated for atrazine and imidacloprid sorption and data fitted to the Freundlich isotherm. The adsorption data was modelled to develop single or multi-staged adsorber plants for pesticide removal from water.Results: Both biochars showed significantly high adsorption capacity for imidacloprid and atrazine. Modelling studies using the Freundlich adsorption parameters suggested that the amounts (kg/1000 L) of RSBC and T-RSBC for 95% of atrazine removal (10 mg/L) in single-, two- and three-staged adsorber plant models were 8.84, 2.44, 1.61 kg and 4.47, 1.42, 0.98 kg, respectively. Corresponding amounts for 95% imidacloprid removal (10 mg/L) were 3.97, 1.22, 0.84 kg and 3.98,1.38, 0.96 kg, respectively. Thus, the two-staged model suggested 65-72% reduction in amount of adsorbent required over the single stage model, while the three-staged model suggested 30-34% adsorbent saving over the two-staged plant model. Single and two-staged adsorber plant model findings were validated for atrazine removal using T-RSBC. Results suggested that amounts calculated using modelling studies were fairly accurate.Conclusion: Biochars, as low cost adsorbents for atrazine and imidacloprid removal from contaminated water, can be used to develop low cost adsorber plants based on multiple batch sorption systems for the removal of these pesticides. Upscaled use of the 2-stage adsorber plant model will substantially reduce the cost of the treatment process, especially at pesticide concentration