Recovering valuable metal resources from industrial wastewater has environmental and economic significance. Flow-electrode capacitive deionization (FCDI) has been successfully used to remove salt and heavy metals. However, the use of this technology in heavy metal treatment has several limitations, including low selectivity, poor long-term stability, and production of low-quality metal products. In this study, a new strategy for recovering chromium (Cr) from wastewater was proposed using an in-situ reduction method. A liquid membrane chamber (LMC) was introduced into a classic three-chamber FCDI and an extraction solution containing Na2SO3 and NaCl was used to capture Cr in wastewater. During FCDI operation, the CrO42-ions entered the LMC were immediately reduced to Cr3+ and retained in the extraction solution. Completing anions (i.e., Cl- ) in the extraction solution maintained the concentration of SO32-ions, and thereby reducing the consumption of re -agents. The improved FCDI system exhibited satisfactory separation performance and high stability during semi-continuous operation. Freshwater, Cr, and copper were obtained in the separation chamber, LMC, and flow electrode chamber, respectively. The facile approach may open the doors for the separation and recovery of metal resources from water/wastewater with high scalability and universality.

Low electron-transfer efficiency and cumbersome processes are widely known to negatively affect the application of Fe-based materials for treating electroplating wastewater. In this study, ferrous/ferric hydroxide complex (FHC) was successfully synthesized to greatly improve the electron-transfer efficiency for Cr(VI) removal; meanwhile, the effect of the interlayer type on Cr(VI) removal and the possible removal mechanisms were well investigated. The sulfate interlayer of FHC was shown to strongly promote Cr(VI) removal, with 10.4 % and 29.0 % improvements over those achieved by chloride and carbonate interlayers, respectively, in close association with the amounts of surface structural Fe(II), surface -OH, and adsorbed water. The initial pH value was demonstrated to exert almost no effect on Cr(VI) removal by FHC(SO42-) owing to the buffering effect of the surface -OH. These results were different from some previously reported Cr(VI) removal of Fe-based materials. Moreover, the results of characterization and lab-scale experiments indicated that most of Cr(VI) binds rapidly with the surface -OH owing to electrostatic attraction. The peak at 618 cm(-1) in the FT-IR spectra shifted to 549 cm(-1) and new peaks at 576.79 and 586.39 eV in the XPS spectra were observed after the reaction, which was attributed to the formation of CrOOH and FeCr2O4 owing to reduction and coprecipitation. Pilot-scale experi-ments revealed that the chemical cost and sludge yield during the FHC process decreased by 71.3 % and 54.1 %, respectively, compared with those in the NaHSO3 process. These findings provide new insight for utilizing different interlayers to improve the reactivity of FHCs in remediating electroplating wastewater containing Cr (VI).

Electro-enhanced metal-free boron/peroxymonosulfate (B/PMS) system has demonstrated potential for efficient metal-organic complexes degradation in an eco-friendly way. However, the efficiency and durability of the boron activator are limited by associated passivation effect. Additionally, the lack of suitable methods utilizing in-situ recovery of metal ions liberated from decomplexation causes huge resource waste. In this study, B/PMS coupled with a customized flow electrolysis membrane (FEM) system is proposed to address above challenges with Ni-EDTA used as the model contaminant. Electrolysis is confirmed to remarkably promote the activation performance of boron towards PMS to efficiently generate •OH which dominated Ni-EDTA decomplexation in the anode chamber. It is revealed that the acidification near the anode electrode improves the stability of boron by inhibiting passivation layer growth. Under optimal parameters (10 mM PMS, 0.5 g/L boron, initial pH = 2.3, current density = 68.87 A/m2), 91.8% of Ni-EDTA could be degraded in 40 min, with a kobs of 6.25 × 10−2 min−1. As the decomplexation proceeds, nickel ions are recovered in the cathode chamber with little interference from the concentration of co-existing cations. These findings provide a promising and sustainable strategy for simultaneous metal-organic complexes removal and metal resources recovery.

Removing ammonia from black water is one of the most urgent issues before it can be recycled as flushing water. In this study, an electrochemical oxidation (EO) process with commercial Ti/IrO2-RuO2 anodes to treat black water could remove 100

Low electron transfer efficiency and cumbersome processes are widely known to negatively affect the application of iron-based materials in the treatment of electroplating wastewater. In this study, ferrous/ferric hydroxide complex (FHC) was successfully synthesized to greatly improve the efficiency of electron transfer for Cr(VI) removal; meanwhile, the effect of the anionic interlayer and the possible removal mechanism were well investigated. We revealed that sulfate interlayer can greatly promote Cr(VI) removal of FHC by 10.4% and 29.0% compared to chloride interlayer and carbonate interlayer, respectively. It was innovatively discovered that the inhibitory of complexing agents (in the order of EDTA > CA > NTA > TA > OA) was closely associated with the amount of -OH and/or -COOH. In comparison to dissolved Fe(II), almost no effect of the initial pH value was found due to the buffering effect of the surface -OH. These results were different from some previously reported Cr(VI) removal of Fe(II)-containing minerals. Based on the characterization and batch experiments, the electrostatic attraction of surface -OH to Cr(VI), accompanied by simultaneous reduction by surface structural Fe(II), was responsible for the rapid reaction within the first 2 min and then co-precipitation to the formation of CrOOH and FeCr 2 O 4 . The chemical cost (1.12 $ m -3 ) and the sludge yield (29.14 kg m -3 ) were reduced by 71.3% and 54.1%, respectively, in the pilot-scale experiments using the FHC process compared to the NaHSO 3 process. These findings provided new insight for utilizing the anionic interlayer to improve the activity of FHC to remediate Cr(VI)-containing electroplating wastewater.

Achieving Paris Agreement temperature goals requires carbon neutrality by the middle of the century. Carbon resource recovery from wastewater is recognized as an effective strategy to reach carbon neutrality. However, few technologies can selectively recover high-quality carbon resources from wastewater. Here, we propose a creative Ion-capture electrochemical system (ICES) simply constructed by integrating a Liquid-membrane chamber (LMC) inside that successfully recovers Formic acid (FA) from wastewater containing a high concentration of Cl-. In the charging process, negatively charged HCOO- that enters the LMC will immediately be converted to uncharged HCOOH by obtaining free protons (H+) from the acidic extraction solution, thereby realizing the selective separation of FA from coexisting ions. Under the optimal conditions (i.e., water productivity = 58.8 L/(m(2) h), current density = 13.3 A/m(2) and pH(ext) = 1.62), an FA product with a high concentration (1586-1827 mg/L) and high purity (80.6%-84.1%) was obtained in semi-continuous operation (14.5 h) while sustaining low energy consumption (2.43 kWh/kg FA). In addition, the process can be applied more broadly to the recovery of various carboxylic acids, such as Acetic acid (AA) and Propionic acid (PA), by using alternative extraction solutions (for example, HCl, H2SO4 and HNO3). The results of this study suggest that an array of efficient and multifunctional processes can be developed through modification of traditional cell configurations for carbon resource recovery.

针对百千瓦级大功率燃料电池发动机的氢气系统进行了系统建模及控制策略开发,对大功率燃料电池系统进行架构分析,基于MATLAB/Simulink进行引射器、阳极流道等核心部件的建模,并集成氢气系统整体模型.基于该模型建立大功率燃料电池氢气系统进气与循环控制策略,通过实机测试验证了控制策略可针对工况变化做出快速、准确的响应,且氢气循环量满足氢气系统需求.

阐述了储油库不同回收处置方法在实际使用中的效果.通过数据分析,指出上海采用吸附法+冷凝法的储油库平均处理效率一般维持在95％左右,采用膜分离法+冷凝法的储油库平均处理效率维持在97％左右.针对这两种不同处理方法,建议环保部门采取不同的管理方式,以保证城市环境空气质量.

In the fuel cell system, hydrogen recirculation subsystem is usually used to increase efficiency of hydrogen usage. While the hydrogen recirculation subsystem is a closed circuit that the water might be accumulated, water separator is used necessarily to separate the water and gas at the anode side. As the poor swirling effect caused by the guide vane in commercial separator, a novel water separator for proton exchange membrane fuel cell system is designed and the flow field characteristics of the separator are gained by computational fluid dynamics. The structure of volute inlet and overflow pipe in the novel separator can enhance the swirling flow and increase the tangential velocity. Based on the results, the separation efficiency and steady performance throughout the flow-rate range can be improved by the novel water separator.

依据上海市公交车辆保有量数据,利用典型公交车辆大气污染物排放因子测试及排放清单测算方法,计算得出2015年上海市公交车辆排放CO、NOx、HC、PM2.5计约1.6万t,并在法规和标准、新车、在用车等方面提出了公交车辆环保监管建议.