Magnetic field assisted electrocatalytic oxidation of organic pollutants in electroplating wastewater

To degrade the organic compounds in the electroplating wastewater,magnetic field was tentatively introduced into electrocatalytic oxidation on Ti-PbO2 anode.The magnetic field assisted electrocatalytic oxidation can promote anion movement and the generation of active species,resulting more organic compounds to be oxidized and degraded.Oxidation parameters such as treatment time,current density and initial pH of the wastewater were systematically discussed and optimized.The mineralization of organic compounds is improved by over 15% under a magnetic density of 22 mT while the current density is 50 A/m2,pH is 1.8 and the reaction time is 1.5 h.The results indicate that the magnetic field assisted electrocatalytic oxidation has considerable potential in electroplating wastewater treatment.

Removing cadmium from electroplating wastewater by waste saccharomyces cerevisiae

The appropriate condition and scheme of removing cadmium from electroplating wastewater were investigated by adsorption-precipitation method using waste saccharomyces cerevisiae(WSC) as sorbent. Effect factors on biosorption of cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae and precipitation process of waste saccharomyces cerevisiae after adsorbing cadmium were studied. The results show that removal rate of cadmium is over 88% after 30 min adsorbing under the condition of cadmium concentration 26 mg/L, the dosage of waste saccharomyces cerevisiae 16.25 g/L, temperature 18 ℃, pH 6.0 and precipitation time 4 h. Biosorption-precipitation method is effective to remove cadmium in cadmium-containing electroplating wastewater by waste saccharomyces cerevisiae. The SEM, infrared spectroscopy and Zeta-potential of the cells show that chemical chelating is the main adsorption form; electrostatic attraction, hydrogen bonding and van der Waals force all function in adsorption process; and ―NH2―,―C=O―,―C=O―NH―,―CH3, ―OH are the main adsorption groups.

Treatment of electroplating wastewater

To study the feasibility of treated water being used as rinsing water with CP/ED (chemical precipitation/ electrodialysis) system, the relation between concentration of Cr (Ⅵ) and conductivity of water is investigated, the effect of electrodialysis (ED) for different wastewater is also studied. And several parameters of importance that are relevant to the process are identified. Analysis of ICP (Inductively coupled plasma) and IC (Ion chromatography) shows that the main reason of conductivity increase in CP treated water is the increase of Na+ and Cl- ions. The 93.8%-100% of ions from wastewater both in ED and CP/ED systems was removed successfully. The results of experiments indicate that the CP/ED system is a feasible method for electroplating wastewater treatment, the CP/ED system used as a way of wastwater is not only in favour of environment, but also economic beneficial to achieve.

Effective removal of chromium,copper,and nickel heavy metal ions from industrial electroplating wastewater by in situ oxidative adsorption using sodium hypochlorite as oxidant and sodium trititanate nanorod as adsorbent

Sodium hypochlorite and synthesized sodium trititanate nanorods(Na_(2)Ti_(3)O_(7),186 nm
×1270 nm)were used as the oxidant and adsorbents for in situ oxidative adsorption treatment of actual electroplating wastewater containing Cr(Ⅵ)(2.6-5.2 mg·L^(-1)),Cu^(2+)(2.7-5.4 mg·L^(-1)),and Ni^(2+)(0.2705-0.541 mg·L^(-1))ions at pH of 8.8-9.1 and 20-60℃.The as-synthesized sodium trititanate nanorods were characterized by XRD,HRTEM,N2 adsorption/desorption,SEM,EDX,and zeta potential techniques.The concentrations of heavy metal ions in wastewater were analyzed by ICP technique.After in situ oxidative adsorption treatment under the concentrations of 25 g·L^(-1) for sodium hypochlorite and 125 mg·L^(-1) for sodium trititanate nanorods at 60℃ for 5 h,the heavy metal ion concentrations could be reduced from initial value of 2.6 to final value of 1.92 mg·L^(-1) for Cr(Ⅵ),3.6 to 0.17 mg·L^(-1) for Cu^(2+),and from 0.2705 to 0.097 mg·L^(-1) for Ni^(2+),respectively.Cr(Ⅵ),Cu^(2+) and Ni^(2+) ions could be effectively removed by the in situ oxidative adsorption method.The in situ oxidative adsorption processes of Cr(Ⅵ),Cu^(2+) and Ni^(2+) ions are satisfactorily simulated by the pseudo-second order adsorption kinetics and Langmuir adsorption isotherm,respectively.Adsorption thermodynamics analyses reveal that the oxidative adsorption processes of Cr(Ⅵ),Cu^(2+) and Ni^(2+) ions are spontaneous and endothermic.The oxidation degree of metalcontained complexes influences the values of thermodynamics functions.

Removal of copper ions from electroplating rinse water using electrodeionization

An improved configuration of the membrane stack was adopted in the electrodeionization （EDI） cell to prevent precipitation of bivalent metal hydroxide during the running. The operational parameters that influenced the removal of copper ions from the dilute solution were optimized. The result showed that a moderate decrease in the inlet pH value and a moderate increase in the applied voltage could achieve a better removal effect. The steady process of electroplating wastewater treatment could be achieved with a removal efficiency of more than 99.5% and an enrichment factor of 5-14. The concentration of copper in purified water was less than 0.23 mg/L. This demonstrated the applicability of recovering heavy metal ions and purified water from electroplating effluent for industrial reuse.

臭氧微泡法处理电镀含氰废水工艺研究

采用臭氧微泡法连续处理电镀含氰废水,考察了废水体积流量、臭氧质量流量、UV灯功率密度和反应管道长度等参数影响,用分光光度计对氰离子(CN−)含量进行测定,得出了最佳的工艺条件:当废水体积流量为120 mL·min^(−1)、臭氧的进料质量流量为11 g·min^(−1)、UV紫外线灯的功率密度为35 W·cm^(−1)、反应管道长度20 m时,废水中氰离子含量降为0.098 mg·L^(−1),臭氧利用率为98.2%,达到国家规定排放标准。

电絮凝协同集成膜处理电镀废水技术研究

以东方航空机械加工厂电镀废水为研究对象,开发了电絮凝-集成膜处理工艺。实验表明:电絮凝过程pH=7,电流密度5 A/dm^(2),电极板间距2.5 cm,电解时间35 min,集成膜进水pH=11,工作压力3.5 MPa, COD可降低至56.43 mg/L,悬浮物可降低至35.43 mg/L,两者去除率分别达到了97.42%和98.91%,出水中重金属含量均低于《电镀污染物排放标准》中污染物排放浓度限值。集成膜的再生使用碱液和次氯酸钠溶液清洗2.5 min,再使用盐酸清洗2.5min,膜通量可达到92.5%~98.2%之间。

正弦交流电絮凝处理含锌电镀废水的研究

[目的]电镀废水中的Zn^(2+)污染控制是当前重要的工业水环境技术问题。[方法]采用正弦交流电絮凝技术和自制的电絮凝装置从废水中除去Zn^(2+)。采用数值模拟的研究方法对电絮凝装置进行了流场分析,并通过实验研究了溶液初始pH、电流密度、初始锌离子浓度、反应时间等因素对去除Zn^(2+)的影响,使用响应面优化方案的Box-Behnken设计获得Zn^(2+)最高去除效率的最佳工艺参数。[结果]钛篮孔板大于3层有利于实现电絮凝装置流场均匀分布;在pH=9、含120 mg/dm^(3)Zn^(2+)的模拟废水溶液中,施加电流密度为0.31 A/m2、频率为50 Hz正弦交流电,通电21.3 min,Zn^(2+)的去除率可达到98.80%。[结论]响应面优化可用于正弦交流电絮凝处理含Zn^(2+)废水的过程。

基于物联网的电镀铬镍混合废水浓度监控系统

监测废水中的铬和镍浓度有助于早期发现和处理潜在的问题,减少对自然环境和水资源的污染风险。为此,设计了基于物联网架构的电镀铬镍混合废水浓度监控系统。在指挥层中使用LoRaWAN通信方式连接电化学传感器和监控系统,监控系统可以实时采集废水中的铬和镍浓度数据。在网络层中使用箱线图对指挥层中采集的数据进行异常值识别,并去除这些异常值。为保证数据的安全性和稳定性,通过物联网技术中的监控系统软件协议代码将数据传输至云平台。在云平台中利用孤独森林算法对传输到云平台的数据进行模式识别和监测,通过感知层将废水浓度数据以可视化的形式展示出来,使用户能够直观地了解混合废水的浓度情况。实验结果表明,本文系统的监测准确度保持在95%以上,且数据传输效率保持在96%以上,具有较高监测准确度的同时具有良好的运行性能。

鸟粪石结晶法回收电镀废水中氮磷试验研究

采用鸟粪石结晶法回收电镀废水中的氮磷,主要考察了pH、重金属离子浓度、氟离子质量浓度对电镀废水中氮磷去除的影响,结果表明pH和重金属离子浓度可显著影响鸟粪石结晶过程,低质量浓度氟离子(0~40 mg/L)对鸟粪石结构的影响可以忽略。对不同条件下形成的鸟粪石进行了XRD、SEM、XPS表征,分析了重金属离子和氟离子对鸟粪石结晶过程的影响机理。重金属离子与鸟粪石可发生共沉淀,干扰鸟粪石结晶的形成。当氟离子与重金属离子共存时,氟离子会影响重金属离子在晶体上的吸附,并生成非晶相共沉淀物,改变鸟粪石的晶体形态。该研究为鸟粪石结晶法回收电镀废水中的氮磷提供理论依据。

正渗透协同电还原处理电镀含铬废水效能探究

针对电镀废水中的六价金属铬危害大、难去除的问题,探究利用正渗透(FO)技术截留浓缩模拟含铬废水的性能,结果表明:随着原料液温度和pH的增加,水通量和截留效果均提升。在FO模式、40℃、pH=8.5条件下,可达到13.73 L/(m^(2)·h)的水通量和89.12%的Cr(Ⅵ)截留率。循环实验结果表明,CTA膜处理含铬废水具有可重复利用性。电化学处理实验结果显示,经正渗透浓缩后,Cr(Ⅵ)的去除率达到62.13%,是浓缩之前的2.16倍,是普通浓缩的4.77倍。FO过程中的反向溶质扩散对还原效率提升起到正向促进作用。

Fenton耦合铁碳微电解技术处理电镀废水的工艺优化

以福建某电镀厂镀镍废水为研究对象,采用Fenton耦合铁碳微电解技术对其进行处理,考察了铁投加量、铁碳质量比、初始pH值及H_(2)O_(2)投加量对COD_(Cr)去除率的影响,通过响应面法优化工艺条件,建立二次多项式预测模型,分析各因素间的交互作用,并检验模型的准确性。结果表明,各因素对COD_(Cr)去除率的影响显著性排序为:初始pH值>H_(2)O_(2)投加量>铁碳质量比>铁投加量;当铁投加量为40 g·L^(-1)、铁碳质量比为0.8、初始pH值为4.0、H_(2)O_(2)投加量为30 mmol·L^(-1)时,COD_(Cr)去除率为78.2%,与预测值(78.9%)基本吻合,说明采用响应面法优化得到的工艺条件准确可靠。

粉煤灰基沸石吸附废液中氨氮化物与铜离子的试验研究

开展了粉煤灰基沸石吸附电镀废液中氮氧化物和铜离子的试验研究。结果表明:粉煤灰基沸石吸附铜离子的适宜条件为:pH值8,溶液中铜离子初始质量浓度200 mg/L,吸附时间0.45 h,温度200℃;粉煤灰基沸石吸附氨氮化物的适宜条件为:粉煤灰基沸石投入量8 g/L,pH值8,吸附时间0.60 h,溶液中氨氮化物初始质量浓度150 mg/L;粉煤灰基沸石吸附铜离子的吸附过程为物理吸附过程,粉煤灰基沸石对氨氮化物的吸附是离子交换和物理吸附共同作用的结果。

铜强化铁碳微电解陶粒阴极对硝基苯废水的降解研究

采用电镀法,考察Cu 2+浓度、电流密度、电镀时间对镀层形貌及电镀速率的影响,以SEM-EDS、XRD、CV等分析方法对所获得的铜电镀污泥碳进行表征;并进一步制备三元微电解陶粒,考察不同加铜方式对陶粒性能的影响。结果表明:在Cu 2+浓度为0.15 mol/L、电流密度为12.5 mA/cm 2时镀层均匀、致密;铜电镀掺杂制备的三元微电解陶粒对硝基苯废水的降解有更高的去除效果,在初始pH为3且废水中的硝基苯浓度为100 mg/L时,反应180 min即可达到90.61%的硝基苯去除率,且对硝基苯的降解符合伪一级动力学反应,反应速率常数可达到0.01058 min-1。

A functionalized activated carbon adsorbent prepared from waste amidoxime resin by modifying with H_(3)PO_(4) and ZnCl_(2) and its excellent Cr(Ⅵ)adsorption

With the application of resins in various fields, numerous waste resins that are difficult to treat have been produced. The industrial wastewater containing Cr(Ⅵ) has severely polluted soil and groundwater environments, thereby endangering human health. Therefore, in this paper, a novel functionalized mesoporous adsorbent PPR-Z was synthesized from waste amidoxime resin for adsorbing Cr(Ⅵ). The waste amidoxime resin was first modified with H3PO4 and ZnCl_(2), and subsequently, it was carbonized through slow thermal decomposition. The static adsorption of PPR-Z conforms to the pseudo-second-order kinetic model and Langmuir isotherm, indicating that the Cr(Ⅵ) adsorption by PPR-Z is mostly chemical adsorption and exhibits single-layer adsorption. The saturated adsorption capacity of the adsorbent for Cr(Ⅵ) could reach 255.86 mg/g. The adsorbent could effectively reduce Cr(Ⅵ) to Cr(Ⅲ) and decrease the toxicity of Cr(Ⅵ) during adsorption. PPR-Z exhibited Cr(Ⅵ) selectivity in electroplating wastewater. The main mechanisms involved in the Cr(Ⅵ) adsorption are the chemical reduction of Cr(Ⅵ) into Cr(Ⅲ) and electrostatic and coordination interactions. Preparation of PPR-Z not only solves the problem of waste resin treatment but also effectively controls Cr(Ⅵ) pollution and realizes the concept of “treating waste with waste”.

电镀园区废水微塑料赋存特征及生态风险评估

电镀废水多关注重金属和氰化物等剧毒物质,但对于近年来备受瞩目的微塑料(MPs)污染未受到足够重视。为研究电镀废水处理工艺过程中MPs赋存特征及其生态风险,以粤港澳大湾区某典型电镀工业园区为例,通过对其各类废水及废水处理厂主要处理工艺出水采样调查,采用傅里叶变换红外光谱仪对MPs的丰度、成分和尺寸进行分析。结果表明:①电镀废水中电镀综合废水的MPs丰度[(1.22×10^(7)±3.87×10^(5))个/m^(3)]最高,其次为含镍电镀废水[(8.20×10^(6)±8.59×10^(4))个/m^(3)],废水中MPs主要成分均为聚丙烯(PP)。②废水处理厂MPs总去除率为99.72%,能完全去除尺寸在500μm以上或成分为三元乙丙橡胶(EPDM)和聚四氟乙烯(PTFE)的MPs。主要处理工艺中,气浮对MPs去除率(95.59%)最高,其次为沉淀(83.33%);气浮能有效去除大部分密度较轻的聚合物,沉淀作用对高密度的MPs去除效果更好。电镀废水处理过程中MPs丰度与固体悬浮物(SS)浓度、色度和浊度均存在相关性,而与pH无关。③潜在生态风险评估结果表明,电镀综合废水和含镍电镀废水MPs污染的潜在生态风险极高,需要高度关注;现行电镀废水处理工艺可大幅降低MPs丰度及高危害性聚合物PE数量,显著降低潜在生态风险。研究显示,该电镀园区废水中MPs丰度显著高于生活污水,虽然废水处理工艺能有效降低MPs丰度和潜在生态风险,但相较生活污水,电镀废水中MPs更易负载重金属和毒害性污染物,建议加强对电镀行业MPs污染排放的监管。

PAC-TMF耦合工艺处理电镀锡废水的响应规律研究

采用粉末活性炭(PAC)-管式微滤膜(TMF)耦合工艺处理某电子厂的电镀锡废水,分析了影响PAC-TMF运行的重要因素。在单因素的基础上采用Box-Behnken组合设计法建立数学模型对运行条件进行优化。结果表明:该耦合工艺对Sn^(2+)去除效果大于对COD去除效果。在PAC投加量290 mg/L,错流速度3.5 m/s,产水浓水比1∶25时,COD与Sn^(2+)去除效果较好,分别为80.7%和89.1%,试验数据与模型预测吻合较好,能指导实际生产。

碱性络合态锌镍废水的水质分析

[目的]研究碱性络合态锌镍废水的水质特征。[方法]以国内不同地区电镀园区的碱性络合态锌镍废水为对象,分析了它们的污染物指标特征及不同指标之间的线性关系。[结果]所研究的废水水样的pH均大于11.0,镍、锌离子浓度差异较大,镍离子主要以络合态形式存在,锌离子部分以络合态形式存在,氮主要以有机氮形式存在。碱性络合态锌镍废水的总镍与COD(化学需氧量)、总氮、有机氮及电导率之间无明显的线性关系。[结论]碱性络合态锌镍废水具有高pH和高电导率的特征,宜采用电化学氧化破络法处理。

MPTS改性高岭土吸附剂的制备及其吸附性能研究

为了处理含电镀络合铜废水,以3-巯丙基三甲氧基硅烷(MPTS)为改性剂,对高岭土进行改性,制备了改性高岭土吸附剂,并研究了其对柠檬酸络合铜(E330-Cu)的吸附效果。适宜的高岭土改性条件为:MPTS相对高岭土用量为0.04 mL/g、改性温度50℃、改性时间6 h。改性高岭土吸附剂对E330-Cu适宜的吸附条件为:E330-Cu初始浓度5 mg/L、吸附剂相对用量15 g/L、pH值4.5、吸附时间35 min、吸附温度35℃,此时吸附率达到92.50%。吸附过程满足Langmuir等温吸附模型和准二级动力学模型。吸附剂至少可使用3次,处理后废水可达到国家一级排放标准。研究结果可为含电镀络合铜废水的处理提供有力支撑。

电镀园区PFASs污染特征分析及控制对策

[目的]电镀是全氟和多氟烷基物质(PFASs)污染的主要来源之一。目前对于典型电镀生产工艺过程及其废水处理站的全链条新污染物研究相对不足。[方法]选取珠三角某电镀园区作为研究对象,检测了包括全氟烷基羧酸(PFCAs)、全氟烷基磺酸(PFSAs),以及全氟辛烷磺酸(PFOS)和全氟辛酸(PFOA)的常见替代物在内的30种典型PFASs,分析了其污染特征。[结果]在电镀的各个工序中普遍存在PFASs,其中镀铬工序检出的PFASs种类最多、浓度最高,并且检出了已明令禁止使用的PFOS、PFOA和PFHxS(全氟己烷磺酸)。废水集中处理设施的进水中PFOS和6:2 FTS(全氟辛烷磺酸钠)的检出浓度和检出率最高,显示出相对严重的污染水平。尽管废水集中处理设施对PFASs有一定的协同处理效果,但出水中检测到了进水中未出现的HFPO-DA(2−甲基−3−氧杂全氟己酸),表明PFASs在污水处理系统中的转化过程有待进一步研究。[结论]针对电镀园区的PFASs污染问题,政府可建立新污染物筛查监测和环境风险评估工作制度,电镀园区宜建立入园企业化学物质信息调查登记制度,企业应落实重点管控新污染物清单要求。