电动修复过程中电解质浓度对U(Ⅵ)迁移和能耗的影响

采用了柠檬酸与氯化铁组合的一种复合电解质，研究不同的电解质浓度对U（Ⅵ）的迁移行为和能量利用率的影响.结果表明：柠檬酸和氯化铁的最佳浓度为0.1mol/L CA+0.03mol/L FeCl₃，该浓度时铀的去除效率约为（61.55±0.41）%，累积消耗能量为0.2559kW·h，能量有效利用率β为（0.24±0.02）×10³.采用Visual MNIETQ软件模拟铀在pH值为3.0的柠檬酸和氯化铁溶液中的存在形式，结果表明主要以大量铀-柠檬酸根络合物（UO₂-Citrate^-）和少量的铀酰离子（UO₂²⁺）存在，此时铀主要从阴极向阳极迁移.当氯化铁浓度增加至0.05mol/L时，铀的去除率相应减少，产生此现象与电渗流强度及方向、氢氧化铁胶体吸附等因素有关.相较于单一的柠檬酸和盐酸，以柠檬酸和氯化铁组合的电解液具备去除效率高、浸出毒性低、土壤修复后危害小等优势.

Effect of electrolyte concentration on U(VI) migration behavior and energy utilization in electrokinetic remediation process

A composite electrolyte with citric acid and ferric chloride was used to study the effects of different electrolyte concentrations on U(VI) migration behavior and energy efficiency. The results revealed the optimal concentration combination was 0.1mol/L for citric acid, and 0.03mol/L for FeCl_3. The corresponding removal efficiency of uranium was about (61.55±0.41)%, the cumulative energy consumption was 0.2559kW·h, and the energy utilization ratio β was (0.24±0.02)×10³. Visual MNIETQ software was further used to simulate theaqueous U speciation in citric acid and ferric chloride solutions at pH 3.0. The results showed that a large amount of uranium-citrate complex (UO₂-Citrate^-) and a small amount of uranyl ion (UO₂²⁺) existed in the process, and uranium mainly migrated from cathode to anode. When the concentration of ferric chloride increased to 0.05mol/L, the removal rate of uranium decreased correspondingly. This phenomenon was related to the strength and direction of electroosmotic flow and the adsorption of colloidal hydroxide. Compared with single citric acid and hydrochloric acidelectrolyte, the electrolyte combined with citric acid and ferric chloride has the advantages of higher removal efficiency, lower leaching toxicity and little harm after electrokinetic (EK) remediation.