State Key Laboratory of Solid Waste Reuse for Building Materials, Beijing Building Materials Academy of Sciences Research , Beijing, People's Republic of China.
Henan Key Laboratory for Environmental Pollution Control and Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, School of Environment, Henan Normal University , Xinxiang, Henan Province, People's Republic of China.
J Air Waste Manag Assoc. 2020 Sep;70(9):904-914. doi: 10.1080/10962247.2020.1769767. Epub 2020 Jul 29.
In this study, an effective circulating system was developed to remove heavy metals in medical waste incineration (MWI) fly ash. MWI fly ash (MWIFA)-column experiments were performed to remove Cu, Pb, Zn, Cd, and Ni from MWIFA using EDTA disodium (NaEDTA). Iron-column experiments were conducted to study the removal effect of zero-valent iron on the five heavy metals from washing wastewater. Toxicity Characteristic Leaching Procedure (TCLP) test method was employed to evaluate heavy metals toxicity of MWIFA residues generated after 0-0.2 mol/L NaEDTA solution treated. After being washed by 0.2 mol/L NaEDTA solution, TCLP leaching values of Cu, Pb, Zn, Cd, and Ni were the lowest and satisfied the standard (GB 5085.3-2007), and the leaching values were 58.4 ± 2.0 mg/L, 2.81 ± 0.14 mg/L, 64.3 ± 4.0 mg/L, 0.156 ± 0.005 mg/L, 0.381 ± 0.006 mg/L. Concentrations of Cu, Pb, Zn, Cd, and Ni in iron-column effluent were reduced by 99.7%, 91.6%, 91.6%, 75.4%, and 75.7%, respectively. NaEDTA was recovered and recycled to the removal of heavy metals from MWIFA. Comparing new NaEDTA solution with recycled NaEDTA solution, recycled NaEDTA and water could be reutilized to dispose MWIFA. The removal efficiencies of Cu, Pb, Zn, Cd, and Ni by recycled 0.2 mol/L NaEDTA solution were 67.1%, 68.8%, 63.2%, 73.9%, 50.7%, respectively, the removal efficiencies using recovered NaEDTA decreased by 2.6%, 3.9%, 3.3%, 4.2%, and 1.6%, respectively. Successive batch experiments were also conducted to evaluate industrialization potential and reusable times for recycled NaEDTA. After four recirculation cycles, extraction efficiencies of Pb and Cd (removal efficiency at different cycles divided by removal efficiency of new NaEDTA) declined toward 80%. Results from this research indicated that this circulating system possessed industrialization potential. An effective circulating system was developed to remove heavy metals in MWI fly ash (MWIFA). Integration of NaEDTA with Fe promoted the removal of heavy metals from MWIFA. NaEDTA, NaCl and water were stepwise extracted from iron-column effluent, respectively. Recovered NaEDTA can still effectively remove heavy metals from MWIFA. Results from this research indicated that this circulating system possessed industrialization potential.
在这项研究中，开发了一种有效的循环系统，用于去除医疗废物焚烧（MWI）飞灰中的重金属。通过 EDTA 二钠盐（NaEDTA）对 MWI 飞灰（MWIFA）进行柱实验，以去除 Cu、Pb、Zn、Cd 和 Ni。进行了铁柱实验，以研究零价铁对五种重金属从洗涤废水中的去除效果。采用毒性特征浸出程序（TCLP）试验方法评价 0-0.2mol/L NaEDTA 溶液处理后 MWIFA 残渣中重金属的毒性。用 0.2mol/L NaEDTA 溶液洗涤后，Cu、Pb、Zn、Cd 和 Ni 的 TCLP 浸出值最低，符合标准（GB 5085.3-2007），浸出值分别为 58.4±2.0mg/L、2.81±0.14mg/L、64.3±4.0mg/L、0.156±0.005mg/L、0.381±0.006mg/L。铁柱流出物中 Cu、Pb、Zn、Cd 和 Ni 的浓度分别降低了 99.7%、91.6%、91.6%、75.4%和 75.7%。回收 NaEDTA 并将其循环用于去除 MWI 飞灰中的重金属。与新的 NaEDTA 溶液相比，回收的 NaEDTA 和水可重新用于处理 MWI 飞灰。用回收的 0.2mol/L NaEDTA 溶液的 Cu、Pb、Zn、Cd 和 Ni 的去除效率分别为 67.1%、68.8%、63.2%、73.9%和 50.7%，使用回收的 NaEDTA 的去除效率分别降低了 2.6%、3.9%、3.3%、4.2%和 1.6%。还进行了连续批实验以评估回收 NaEDTA 的工业化潜力和可重复使用次数。经过四个循环，Pb 和 Cd 的萃取效率（不同循环的去除效率除以新 NaEDTA 的去除效率）下降到 80%左右。研究结果表明，该循环系统具有工业化潜力。一种有效的循环系统被开发出来，用于去除医疗废物焚烧（MWI）飞灰（MWIFA）中的重金属。NaEDTA 与 Fe 的结合促进了 MWIFA 中重金属的去除。铁柱流出物依次用 NaEDTA、NaCl 和水进行萃取。回收的 NaEDTA 仍能有效地从 MWIFA 中去除重金属。研究结果表明，该循环系统具有工业化潜力。
