本研究证明了通过简单的三腔电解池将尿素/牛尿用作还原Cr(VI)的阳极电解液的潜在用途。双重废物流(Cr(VI)-尿素/尿液)中固有的化学能用于其自我氧化还原,而无需任何外部能量供应。镍泡沫作为电活性阳极和无催化剂的碳毡作为阴极,随着离子选择性分离器的适当定位,通过阻碍电解质交叉间接改善电池性能。本文进行了涉及五种不同膜结构的基础研究以提高Cr(VI)还原效率。Cr(VI)还原效率为11.84±0.27%,10.55±0.17%,24h时77.24±0.38%,使用玻璃料72h时13.57±0.25%,阳离子交换膜(CEM),夹层膜,和阴离子交换膜(AEM)作为双室H电池中的分离器,分别,初始Cr(VI)浓度为100mg/L第五种配置,由阳极和阴极之间的中间室组成,CEM靠近阳极,AEM靠近阴极,对于初始Cr(VI)浓度为400mg/L,在45分钟内的还原效率为79.98±2.24%。对于100、200和400mg/L的Cr(VI)浓度,一阶速率常数确定为0.024、0.018和0.013min-1,分别。此外,当尿素被牛尿代替作为阳极电解液时,在pH为2的45分钟内,初始Cr(VI)浓度为400mg/L,还原效率为98.94±1.28%。此外,还原Cr的XPS光谱对应于579.4eV和589.3eV的结合能,分别,证实了低毒Cr(III)的存在。施加载荷的影响,初始Cr(VI)和尿素浓度,对不同初始H2SO4浓度下的Cr(VI)还原进行了简洁的研究,以评估电解池的性能。因此,氧化还原电解池可以是用于还原六价铬的常规化学或能量密集型方法的替代方案。
The present study demonstrates the potential utilization of urea/cow urine as anolyte for Cr(VI) reduction via a simple three-chambered electrolytic cell. The inherent chemical energy in the dual-waste stream (Cr(VI)-urea/urine) is employed for its self-oxidation-reduction without the need for any external energy supply. Ni foam as electroactive anode and catalyst-free carbon felt as cathode, along with the appropriate positioning of ion-selective separators, indirectly improved the cell performance by impeding electrolyte crossover. A fundamental study involving five different membrane configurations was conducted herein to improve Cr(VI) reduction efficiency. The Cr(VI) reduction efficiencies were 11.84 ± 0.27%, 10.55 ± 0.17%, 77.24 ± 0.38% at 24 h, 13.57 ± 0.25% at 72 h with glass frit, cation exchange membrane (CEM), sandwiched membrane, and anion exchange membrane (AEM) as separators in a dual-chambered H-cell, respectively, with an initial Cr(VI) concentration of 100 mg/L. The fifth configuration, consisting of a middle chamber between the anode and cathode with the CEM close to the anode and the AEM close to the cathode resulted in a reduction efficiency of 79.98 ± 2.24% within 45 min for an initial Cr(VI) concentration of 400 mg/L. The first order rate constants were determined to be 0.024, 0.018, and 0.013 min-1 for Cr(VI) concentrations of 100, 200, and 400 mg/L, respectively. Moreover, when urea was replaced with cow urine as anolyte, a reduction efficiency of 98.94 ± 1.28% was achieved at pH 2 in 45 min with 400 mg/L as initial Cr(VI) concentration. Furthermore, the XPS spectra of reduced Cr corresponding to binding energies of 579.4 eV and 589.3 eV, respectively, confirmed the presence of low-toxic Cr(III). The effect of applied load, initial Cr(VI) and urea concentration, Cr(VI) reduction under different initial H2SO4 concentrations were succinctly investigated to evaluate the performance of the electrolytic cell. The redox electrolytic cell can thus be an alternative to the conventional chemical or energy intensive processes for the reduction of hexavalent chromium.