Centre for Agroecology Water and Resilience (CAWR), Coventry University, Wolston Lane, Ryton on Dunsmore, CV8 3LG, UK.
Centre for Agroecology Water and Resilience (CAWR), Coventry University, Wolston Lane, Ryton on Dunsmore, CV8 3LG, UK.
J Environ Manage. 2021 Mar 15;282:111950. doi: 10.1016/j.jenvman.2021.111950. Epub 2021 Jan 16.
Dissolved copper in stormwater runoff is a significant environmental problem. Biosorption of dissolved metals using microorganisms is known as a green, low-cost and efficient method. However, the role of live biological agents in the remediation of dissolved copper in Sustainable Drainage (SuDS) has not been reported. In this study, the effect of pH, initial concentration and temperature, on bacteria in different stages of biofilm development on a geotextile, along with Cu(II) removal efficiencies, were evaluated. Maximum Cu(II) removal efficiency (92%) was observed at pH 6. By decreasing the pH from 6 to 2, a log 5 reduction in bacteria was observed and Carboxyl groups transformed from -COO to -COOH. The maximum biosorption capacity (119 mg g) was detected on day 1 of biofilm development, however, maximum removal efficiency (97%) was measured on day 21 of biofilm incubation. Exteracellular Polymeric Substance (EPS) showed a better protection of CFUs in more mature biofilms (day 21) with less than 0.1 log decrease when exposed to 200 mL Cu(II), whereas, biofilm on day 1 of incubation showed a 2 log reduction in CFUs number. Thermodynamic studies showed that the maximum Cu(II) biosorption capacity of biofilms, incubated for 7 days (117 mg g) occurred at 35 °C. Thermodynamic and kinetic modelling of data revealed that a physical, feasible, spontaneous and exothermic process controlled the biosorption, with a diffusion process observed in external layers of the biofilm, fitting a pseudo-second order model. Equilibrium data modelling and high R values of Langmuir model indicated that the biosorption took place by a monolayer on the living biofilm surface in all stages of biofilm development.
雨水径流水体中的溶解铜是一个重大的环境问题。利用微生物吸附溶解金属是一种绿色、低成本、高效的方法。然而，活体生物制剂在可持续排水 (SuDS) 中修复溶解铜的作用尚未有报道。在本研究中，评估了不同生物膜发育阶段的细菌在土工织物上对 pH 值、初始浓度和温度的响应，以及 Cu(II)去除效率。在 pH 值为 6 时观察到最大的 Cu(II)去除效率（92%）。当 pH 值从 6 降低到 2 时，观察到细菌对数减少 5，羧基基团从 -COO 转变为 -COOH。在生物膜发育的第 1 天检测到最大的生物吸附容量（119mg/g），然而，在生物膜培养的第 21 天测量到最大的去除效率（97%）。胞外聚合物质 (EPS) 在更成熟的生物膜（第 21 天）中为 CFU 提供了更好的保护，暴露于 200mL Cu(II)时，CFU 数量的减少不到 0.1 对数，而在培养的第 1 天的生物膜则显示 CFU 数量减少了 2 对数。热力学研究表明，培养 7 天的生物膜（117mg/g）对 Cu(II)的最大吸附容量出现在 35°C。数据的热力学和动力学建模表明，生物吸附过程由物理、可行、自发和放热控制，在生物膜的外部层观察到扩散过程，符合准二级模型。平衡数据建模和 Langmuir 模型的高 R 值表明，在生物膜发育的所有阶段，生物吸附都是在活生物膜表面上发生的单层吸附。
