Environmental and Water Resources Engineering Division, Department of Civil Engineering, IIT Madras, Chennai, 600 036, India.
Environmental and Water Resources Engineering Division, Department of Civil Engineering, IIT Madras, Chennai, 600 036, India.
J Environ Manage. 2020 Nov 1;273:111039. doi: 10.1016/j.jenvman.2020.111039. Epub 2020 Aug 1.
In the present study, efficiency of electro-coagulation-flotation (EC-F) process using waste metal scrap of Al and Fe collected from construction and demolition waste of Indian Institute of Technology Madras (IIT M) campus for the removal of double azo bond dye Acid Red 66 (AR66) was studied. The key operating parameters such as current density and electrical conductivity were optimized individually with an initial dye concentration of 50 mg/L, at pH 7. Different electrode combinations and connection modes (parallel MP-P, series (MP-S, BP-S)) were tested, at pre-optimized conditions, in order to achieve better removal of AR66 dye with minimum energy consumption. Series connection in bipolar electrode mode (BP-S) showed better COD reduction from 164 mg/L to 26.2 mg/L with complete decolourization (BDL). Hybrid electrode system of Fe-Al-Fe-Al-Fe-Al showed maximum reduction of COD from 164 mg/L to 11.3 mg/L along with 86.3% TSS reduction and complete decolourization. LC-MS analysis showed the formation of intermediates with m/z 195, m/z 210.6 and m/z 159.3 due to the destruction of AR66 dye during electrolysis. Highest current efficiency (CE φ = 107%) was observed in case of hybrid electrode system compared to Al (φ = 30.1%) and Fe (φ = 98.3%) electrode system at similar operating conditions. Compared to the same electrode material as anode and cathode, use of appropriate hybrid electrode combination can improve the removal efficiency and reduce the energy consumption (ENC). The influence of aeration on the performance of the system was also studied. Aeration significantly improved the COD removal efficiency (98.3%) along with complete decolourization (100%). The use of waste metal scrap as electrodes reduced the overall cost of the treatment process from 1.6 $/m to 0.06 $/m. Using waste metal scrap as electrodes not only reduces the metal accumulation in the environment but also reduces the cost of EC-F process.
在本研究中，使用从印度马德拉斯理工学院（IIT M）校园的建筑和拆除废物中收集的废金属废料（Al 和 Fe）的电凝聚浮选（EC-F）过程的效率，用于去除双偶氮键染料酸性红 66（AR66）。优化了关键操作参数，例如电流密度和电导率，初始染料浓度为 50mg/L，pH 值为 7。在预优化条件下，测试了不同的电极组合和连接方式（并联 MP-P、串联（MP-S、BP-S）），以实现更好的 AR66 染料去除效果，并最小化能耗。双极电极模式（BP-S）的串联连接显示出更好的 COD 去除效果，从 164mg/L 降至 26.2mg/L，同时完全脱色（BDL）。Fe-Al-Fe-Al-Fe-Al 混合电极系统显示出最大的 COD 去除效果，从 164mg/L 降至 11.3mg/L，同时 TSS 去除率为 86.3%，完全脱色。LC-MS 分析表明，由于 AR66 染料在电解过程中被破坏，形成了 m/z 195、m/z 210.6 和 m/z 159.3 的中间体。在相似的操作条件下，与 Al（φ=30.1%）和 Fe（φ=98.3%）电极系统相比，混合电极系统的电流效率（CEφ=107%）最高。与相同的电极材料作为阳极和阴极相比，适当的混合电极组合的使用可以提高去除效率并降低能耗（ENC）。还研究了曝气对系统性能的影响。曝气显著提高了 COD 去除效率（98.3%），同时完全脱色（100%）。使用废金属废料作为电极不仅减少了环境中的金属积累，而且降低了 EC-F 过程的成本。
