零极距非对称阴极电化学除垢性能优化与机理

doi:10.16085/j.issn.1000-6613.2024-0672

摘要/Abstract

摘要：

电化学除硬是一种新型的绿色工业循环冷却水阻垢技术，但是传统单腔室电解过程产生的H⁺、OH^-无法高效分离，导致电化学除硬效率低、能耗高。对此，构建零极距、非对称式电解反应体系，单侧绝缘的非对称阴极调控H₂气泡的定向运动，驱动OH^-向一侧溶液扩散，而三维阳极区域内利用重力渗流作用将电解产生的H⁺带离反应区域，通过数学模型理论计算证明OH^-和H⁺分别在阴极氢气泡作用下的对流传质速率和在重力渗流作用下的迁移速率都高于其电迁移速率，从而实现H⁺、OH^-的高效分离，提升了OH^-的除硬利用率。实验结果表明，当电流密度为15mA/cm²、流速为15mL/min时，钙硬去除率和去除速率分别高达89.2%和267.5g/(h·m²)，而能耗仅为3.27kW·h/kg。本研究利用气泡运动和水流调控策略开发了一种高效的电化除硬装置，为电化学循环冷却水除垢反应器开发提供新思路。

关键词: 电化学, 水软化, 非对称电极, 扩散, 流体动力学

Abstract:

Electrochemical water softening represents an innovative and green approach for the descaling of industrial circulating cooling water system. However, in the undivided electrolytic cell, the generated H⁺ and OH^- at anode and cathode, respectively, cannot effectively separate, causing low water softening efficiency and high energy consumption. In this study, an asymmetric cathodic electrochemical water softening with zero electrode space was developed, which was consisting of a unilaterally insulated asymmetric cathode and particles packed anode. In this electrolytic reactor, the directional motion of H₂ bubbles from the asymmetric cathode could drive OH^- diffusion to the solution at the back of the cathode, while H⁺ could be carried away from the interface between anode and cathode by the gravitational seepage in the three-dimensional anode region. Theoretical calculations based on a mathematical model proved that transport rates of OH^- and H⁺ away from the electrodes induced by the H₂ bubble and gravitational seepage, respectively, were greater than their corresponding electro-migration rates. Thus, H⁺ and OH^- were effectively separated with high utilization of OH^- for hardness precipitation. The experimental results showed that the calcium hardness removal efficiency and removal rate were as high as 89.2% and 267.5g/(h·m²), respectively, at a current density of 15mA/cm² and a flow rate of 15mL/min, with an energy consumption of only 3.27kW·h/kg. An efficient electrochemical water softening reactor with using bubble motion and flow regulation strategies was developed, providing new idea for the design of electrochemical circulating cooling water descaling reactor.

Key words: electrochemical, water softening, asymmetric electrodes, diffusion, hydrodynamics

中图分类号:

魏方熙, 刘倩楠, 吴亚品, 吴静丽, 宋文清, 唐沂珍, 江波. 零极距非对称阴极电化学除垢性能优化与机理[J]. 化工进展, 2025, 44(6): 3642-3650.

WEI Fangxi, LIU Qiannan, WU Yapin, WU Jingli, SONG Wenqing, TANG Yizhen, JIANG Bo. Asymmetric cathodic electrochemical water softening with zero electrode space: performance optimization and mechanism[J]. Chemical Industry and Engineering Progress, 2025, 44(6): 3642-3650.

图/表 7

图1 电化学软化装置

图2 反应器阴极、阳极区域进出水方式（Ⅰ）阴、阳极同时下进上出；（Ⅱ）阴、阳极同时上进下出；（Ⅲ）阴极下进上出，阳极上进下出；（Ⅳ）阴极上进下出，阳极下进上出

图3 不同操作模式下酸碱出水pH［10mmol/L硫酸钠(a)，模拟循环水(b)］和钙硬度去除率和碳酸钙沉积速率(c)

图4 电极尺寸对钙硬度去除率、沉积速率[（a）（d）]，碱度去除率[（b）（e）]，能耗、电流效率[（c）（f）]的影响（实验条件：10mmol/L Na2SO4，钙硬度400mg/L，镁硬度100mg/L，碱度300mg/L，pH 8.00，流速15mL/min，电流密度15mA/cm2，进出水模式Ⅲ）

图5 电流密度对酸碱出水pH(a)、钙硬度去除率和碳酸钙沉积速率(b)、碱度去除率(c)、能耗和电流效率(d)的影响（实验条件：10mmol/L Na2SO4，钙硬度400mg/L，镁硬度100mg/L，碱度300mg/L，pH=8.00，流速15mL/min，进出水模式Ⅲ）Ji=-Di∇ci-Ziμici∇ϕ+ci (6)

图6 流速对出水溶液pH(a)、钙硬度去除率和碳酸钙沉积速率(b)、碱度去除率(c)、能耗和电流效率(d)的影响（实验条件：10mmol/L Na2SO4，钙硬度400mg/L，镁硬度100mg/L，碱度300mg/L，pH 8.00，电流密度15mA/cm2，进出水模式Ⅲ）

图7 不同电流密度下OH-的气泡扩散速率及电迁移速率(a)；不同泵抽取速率下H+的重力渗流迁移速率及电迁移速率(b)

参考文献 30

[1]	WANG Liangtian, ZHOU Jie, CHANG Yuexin, et al. Research progress on novel electrochemical descaling technology for enhanced hardness ion removal[J]. Water, 2024, 16(6): 886.
[2]	郭丰源, 徐剑锋, 徐敏, 等. 我国工业用水现状、问题与节水对策[J]. 环境保护, 2022, 50(6): 58-63.
	GUO Fengyuan, XU Jianfeng, XU Min, et al. Present situation, problems and water-saving countermeasures of industrial water use in China[J]. Environmental Protection, 2022, 50(6): 58-63.
[3]	JIANG Bo, REN Xuanzhen, LIU Qiannan, et al. Electrochemical water softening technology: From fundamental research to practical application[J]. Water Research, 2024, 250: 121077.
[4]	毛伟, 于洪涛. 电化学水软化技术的现存问题与对策[J]. 工业水处理, 2023, 43(7): 32-40.
	MAO Wei, YU Hongtao. Emerging problems and strategies of electrochemical water softening technology[J]. Industrial Water Treatment, 2023, 43(7): 32-40.
[5]	徐勇, 陈青柏, 王建友. 离子交换水软化技术研究与应用进展[J]. 化工进展, 2020, 39(S2): 319-328.
	XU Yong, CHEN Qingbai, WANG Jianyou. Research and application progress in the technology of water softening by ion exchange[J]. Chemical Industry and Engineering Progress, 2020, 39(S2): 319-328.
[6]	苏晴, 颜薇, 唐沂珍, 等. 电化学-微滤耦合工艺对循环水钙硬度的结晶分离[J]. 化工进展, 2022, 41(2): 1036-1042.
	SU Qing, YAN Wei, TANG Yizhen, et al. Electrochemical-microfiltration coupling process for the crystal separation of calcium hardness in circulating cooling water[J]. Chemical Industry and Engineering Progress, 2022, 41(2): 1036-1042.
[7]	BA Xuchen, CHEN Jinghua, WANG Xuesong, et al. Anode boundary layer extraction strategy for H⁺-OH-separation in undivided electrolytic cell: Modeling, electrochemical analysis, and water softening application[J]. ACS ES&T Eng, 2023, 3(12): 2183-2193.
[8]	TLILI M M, BENAMOR M, GABRIELLI C, et al. Influence of the interfacial pH on electrochemical CaCO₃ precipitation[J]. Journal of the Electrochemical Society, 2003, 150(11): C765-C771.
[9]	栾谨鑫, 李鑫浩, 王立达, 等. 复合网状阴极增强电化学水软化系统性能研究[J]. 工业水处理, 2020, 40(2): 67-70.
	LUAN Jinxin, LI Xinhao, WANG Lida, et al. Research on enhanced performance of electrochemical water softening system by multi-meshes coupled cathodes[J]. Industrial Water Treatment, 2020, 40(2): 67-70.
[10]	ZASLAVSCHI Irina, SHEMER Hilla, HASSON David, et al. Electrochemical CaCO₃ scale removal with a bipolar membrane system[J]. Journal of Membrane Science, 2013, 445: 88-95.
[11]	HASSON David, SEMIAT Raphael. Scale control in saline and wastewater desalination[J]. Israel Journal of Chemistry, 2006, 46(1): 97-104.
[12]	LIU Yijie, NIU Qinghe, ZHU Juntao, et al. Efficient and green water softening by integrating electrochemically accelerated precipitation and microfiltration with membrane cleaning by periodically anodic polarization[J]. Chemical Engineering Journal, 2022, 449: 137832.
[13]	Ignacio SANJUÁN, BENAVENTE David, Eduardo EXPÓSITO, et al. Electrochemical water softening: Influence of water composition on the precipitation behaviour[J]. Separation and Purification Technology, 2019, 211: 857-865.
[14]	XU Hao, XU Zhicheng, GUO Yifei, et al. Research and application progress of electrochemical water quality stabilization technology for recirculating cooling water in China: A short review[J]. Journal of Water Process Engineering, 2020, 37: 101433.
[15]	沈建阳. 304不锈钢超疏水表面涂层制备及其阻垢性能研究[D]. 上海: 东华大学, 2023.
	SHEN Jianyang. Preparation of superhydrophobic surface coating on 304 stainless steel and research on its scale inhibition performance[D]. Shanghai: Donghua University, 2023.
[16]	PAWLOWSKI Sylwin, SISTAT Philippe, CRESPO João G, et al. Mass transfer in reverse electrodialysis: Flow entrance effects and diffusion boundary layer thickness[J]. Journal of Membrane Science, 2014, 471: 72-83.
[17]	YIN Fengjun, LIU Hong. The j-pH diagram of interfacial reactions involving H⁺ and OH^- [J]. Journal of Energy Chemistry, 2020, 50: 339-343.
[18]	VOGT H. Mass transfer at gas evolving electrodes with superposition of hydrodynamic flow[J]. Electrochimica Acta, 1978, 23(3): 203-205.
[19]	RIEGEL H, MITROVIC J, STEPHAN K. Role of mass transfer on hydrogen evolution in aqueous media[J]. Journal of Applied Electrochemistry, 1998, 28(1): 10-17.
[20]	SUN Wei, MA Liang, HU Yuehua, et al. Hydrogen bubble flotation of fine minerals containing calcium[J]. Mining Science and Technology (China), 2011, 21(4): 591-597.
[21]	YANG Kui, ZHANG Xinyuan, ZU Daoyuan, et al. Shifting emphasis from electro- to catalytically active sites: Effects of pore size of flow-through anodes on water purification[J]. Environmental Science & Technology, 2023, 57(48): 20421-20430.
[22]	CHANDRAN Prasad, BAKSHI Shamit, CHATTERJEE Dhiman. Study on the characteristics of hydrogen bubble formation and its transport during electrolysis of water[J]. Chemical Engineering Science, 2015, 138: 99-109.
[23]	陈延禧, 沈曼丽, 陈艳英, 等. 用激光衍射法研究电解气泡的大小及其分布[J]. 化学学报, 1992, 50(10): 967-972.
	CHEN Yanxi, SHEN Manli, CHEN Yanying, et al. Study on electrolytic bubble size and its distribution by means of laser diffraction method[J]. Acta Chimica Sinica, 1992, 50(10): 967-972.
[24]	CHEN Jinghua, CHENG Zishen, YUAN Wenjuan, et al. High-flux electrochemical phosphorus recovery in an undivided electrolytic cell coupled with microfiltration with low energy consumption[J]. Chemical Engineering Journal, 2024, 484: 149801.
[25]	KANG Wenda, LI Lujie, YAN Liming, et al. Spatial and temporal regulation of homogeneous nucleation and crystal growth for high-flux electrochemical water softening[J]. Water Research, 2023, 232: 119694.
[26]	PACH L, DUNCAN S, ROY R, et al. Morphological control of precipitated calcium carbonates and phosphates by colloidal additives[J]. Journal of Materials Science, 1996, 31(24): 6565-6569.
[27]	BHATTACHARJEE Saikat, MONDAL Sourav, DE Sirshendu. Electro-kinetically enhanced mass transport of charged macro-solutes through a microchannel with porous walls[J]. AIChE Journal, 2023, 69(3): e17899.
[28]	ALBUQUERQUE I L T, CAVALCANTI E B, VILAR E O. Mass transfer study of electrochemical processes with gas production[J]. Chemical Engineering and Processing: Process Intensification, 2009, 48(9): 1432-1436.
[29]	PARK Sunghak, LIU Luhao, Çayan DEMIRKıR, et al. Solutal Marangoni effect determines bubble dynamics during electrocatalytic hydrogen evolution[J]. Nature Chemistry, 2023, 15(11): 1532-1540.
[30]	李新海, 陈新民. 汞电极上气泡生长与逸出过程的动力学行为[J]. 有色金属, 1993(3): 43-48.
	LI Xinhai, CHEN Xinmin. Kinetic behaviour of bubble growth and evolution on mercury electrode[J]. Nonferrous Metals, 1993(3): 43-48.