Plating Effluent Research Articles

Structural modification of defective WO3 by g-C3N4 for photocatalytic gold recovery from non-cyanide-based plating effluent

A set of nCN/WO3 − x composites was synthesized through a simple thermal treatment for gold recovery from the simulated effluent of a non-cyanide-based plating bath. The obtained results exhibited that all nCN/WO3 − x composites demonstrated a higher photocatalytic activity for gold recovery than their pristine components due to the formation of nanocomposites which paved a convenient pathway for charge transfer. Among all synthesized composites, the 5.0CN/WO3 − x composite exhibited the highest photocatalytic activity, recovering around 69.4% of gold within 120 min under UV-vis light irradiation at an intensity of 3.45 mW/cm² and a catalyst loading of 1.0 g/L, in the absence of hole scavenger. This result can be ascribed to the presence of an optimal number of defects, which can act as electron trapping sites and thereby reduce the recombination rate of charge carriers. Gold recovery increased with repeated reuse, attributed to the decorated gold, which enhances light absorption and decreases the recombination rate of charge carriers. The feasible application of used CN/WO3 − x were also explored for H2 production, dye degradation and gold recovery. The obtained results provide a new insight about the photocatalytic recovery of gold from industrial wastewater and also shed light on the application of gold-decorated CN/WO3 − x as a catalyst for other photocatalytic applications.

Performance of crosslinked bentonite-biocarbon electrodes for chromium mitigation through electrosorption

ABSTRACT Electrosorption has emerged as an energy-efficient technology for water deionization, yet high electrode costs limit its industrial adoption. The present study introduces a sustainable, cost-effective electrode design by crosslinking bentonite – a natural, stable clay mineral – with rice straw-derived biocarbon (ZC-B) to enhance chromium (Cr(VI)) removal from wastewater. The ZC-B electrodes exhibited a high specific surface area (580 m2/g), mesoporous structure, and significant specific capacitance (~68 F/g), optimized for Cr(VI) removal. Electrosorption tests demonstrated remarkable efficacy, achieving 99.57% Cr(VI) removal at 25 ppm and 90.02% at 250 ppm, with electrosorption capacities of 4.92 mg/g and 52.73 mg/g. Real-world trials on chrome plating effluent confirmed the ZC-B electrode’s potential for industrial-scale Cr(VI) remediation, adhering to disposal standards. This work establishes bentonite-modified biocarbon as a promising, eco-efficient solution for heavy metal removal through electrosorption.

Highly-efficient recovery of silver from industrial cyanide-based plating effluent on TiO2/activated carbon composites

The release of silver-containing wastewater is an economic loss. In this works, the silver ions in the cyanide-based plating effluent of jewelry effluent was systematic recovered by the photocatalytic process using commercial semiconductors (TiO2, ZnO, Bi2O3 and WO3) and activated carbon (AC) enhanced semiconductors as the photocatalysts. The preliminary results demonstrated that the highest photocatalytic silver recovery was achieved via the use of TiO2 nanoparticles (NPs), ascribing to its better textural property that provided abundant active sites to undergo the reaction. The intrinsic property and activity of TiO2 were significantly improved in the presence of proper content of AC. Approximately 94% of silver was recovered within 45 min through the TiO2/AC with 14.9 wt% AC (TiO2/AC1) under the UV–vis irradiation due to the act of AC as the conductive pathway for electron migration from CB of TiO2 along its surface, thus prolonging the lifetime of electron-hole pairs. Although a marked decrease in photocatalytic activity of the best composite was detected after the 4th use (∼50%), it exhibited an outstanding antibacterial ability compared with TiO2 and fresh one in dark environment. The work offers the avenue to design the photocatalyst for recovering the precious metals from industrial effluent and broaden the application of such recovered metal decorated photocatalyst for practical use.

Synthetic Cu(III) from copper plating wastewater for onsite decomplexation of Cu(II)- and Ni(II)-organic complexes

Herein, the Cu(III) synthesized from copper plating effluent was developed for the first time to evaluate the onsite degradation performance of heavy metal complexes in the wastewater, thus achieving the purpose of “treating waste with waste”. The results indicated that synthetic Cu(III) presented the excellent decomplexation performance for Cu(II)/Ni(II)-organic complexes. The removal efficiency of Cu(II)/Ni(II)-EDTA significantly increased with increasing Cu(III) dosage, and the degradation of Cu(II)/Ni(II)-EDTA by synthetic Cu(III) system displayed highly pH-dependent reactivity. The radical quencher experiments confirmed that Cu(III) direct oxidation were mainly involved in the degradation of Cu(II)-EDTA. Additionally, the continuous decarboxylation process was proven to be the main degradation pathway of Cu(II)-EDTA in Cu(III) system. The coexisting substances (SO42−, Cl− and fulvic acids) showed little impacts at low level for the removal of Cu(II)/Ni(II)-EDTA, while retarded the degradation of Cu(II)-EDTA slightly at high level, which features high selective oxidation. Encouragingly, it was also effective to remove Cu(II)/Ni(II)-EDTA from in treating actual Cu/Ni-containing wastewater through synthetic Cu(III) treatment.

Photocatalytic application of defective WO3 nanoparticles for precious metal recovery from plating effluent

BackgroundPlating units of electronics industry generally release wastewater with various types of metal ions and sometimes precious metal ions such as gold. Discharging of gold-containing wastewater is an economic loss. Accordingly, the photocatalytic process has emerged as the effective process to recover gold ions. MethodsThe defective WO3 NPs were synthesized by sequential process of acid precipitation and annealing method to recover gold from a cyanide-free plating bath solution. The impacts of annealing temperatures and operating conditions on the photocatalytic property and activity of WO3 NPs were explored. Significant findingsAn annealing temperature in the range of 650 – 950 °C did not significantly affect the surface property of the WO3 samples, but remarkably impacted the optical property. A high temperature induced the generation of W5+ and oxygen vacancies in the WO3 structure, promoting the visible light response. Among all synthesized samples, the WO3 sample annealed at 850 °C (W85) exhibited the superior photocatalytic activity to recover gold up to 90.8 % at photocatalyst loading of 2 g/L, initial pH of effluent of 9.2, C2H5OH concentration of 10 vol.% in the presence of 6 mM Na2S2O3. In addition, the W85 sample possessed consistent stability to recover gold from the plating effluent even at the 5th cycle.

Photocatalytic Gold Recovery from Industrial Gold Plating Effluent by ZnO Nanoparticles: Optimum Condition and Possible Applications.

The comparative study of photocatalytic gold recovery from cyanide-based gold plating solution was explored via commercial and hydrothermally synthesized ZnO nanoparticles (NPs). The effects of hydrothermal temperatures on the properties and photocatalytic activities of synthesized ZnO NPs were investigated. In addition, the effects of operating parameters including types of hole scavenger, concentrations of the best hole scavenger, the initial pH of wastewater, and photocatalyst dosages were examined. The obtained results demonstrated that the commercial ZnO NPs exhibited a higher photocatalytic activity for gold recovery than that of the synthesized ones owing to their good crystal quality and the presence of non-lattice zinc ions and appropriate non-lattice oxygen ions. Via the commercial ZnO NPs, the gold ions were almost completely recovered from the cyanide-based gold plating effluent within 7 h at an initial pH of 11.0 in the presence of 10 vol % C2H5OH and 1.0 g/L of photocatalyst loading with a pseudo-first-order rate constant of 0.2637 h-1. Finally, the resultant gold-decorated ZnO NPs exhibited a higher photocatalytic property for color reduction from industrial wastewater and antibacterial activity than that of fresh ZnO NPs. The results obtained in this study possess benefits and pave the way for waste remediation and management for the plating industries.

Highly efficient decomplexation of chelated nickel and copper effluent through CuO–CeO2–Co3O4 nanocatalyst loaded on ceramic membrane

A novel CuO–CeO2–Co3O4 nanocatalyst loaded on Al2O3 ceramic composite membrane (CCM-S) was synthesized through spraying-calcination method, which can be beneficial to the engineering application of scattered granular catalyst. BET and FESEM-EDX testing revealed that CCM-S possessed a porous character with high BET surface area of 22.4 m2/g and flat modified surface with extremely fine particle aggregation. The CCM-S calcined above 500 °C presented excellent anti-dissolution effect due to the formation of crystals. XPS indicated that the composite nanocatalyst possessed the variable valence states, which were conducive to exert the catalytic effect of Fenton-like reaction. Subsequently, the effects of experimental parameters including fabricate method, calcination temperature, H2O2 dosage, initial pH value, and CCM-S amount were further investigated considering the removal efficiency of Ni(II)-complex and COD after decomplexation and precipitation (pH = 10.5) treatment within 90 min. Under the optimal reaction condition, the residual Ni(II)-complex and Cu(II)-complex concentration from actual wastewater was all lower than 0.18 mg/L and 0.27 mg/L, respectively; meanwhile, the removal efficiency of COD was all higher than 50% in the mixed electroless plating effluent. Besides, the CCM-S could still maintain high catalytic activity after a six-cycle test, and the removal efficiency was slightly declined from 99.82% to 88.11%. These outcomes indicated that CCM-S/H2O2 system was provided with a potential applicability on treatment of real chelated metal wastewater.

A novel green synergistic extraction formulation based on D2EHPA for recovering nickel from nickel plating effluent

A new green synergistic extraction agent (di-2-ethylhexyl phosphoric acid (D2EHPA)—decanol) was developed to recycle Ni(II) from nickel plating effluent. The results show that the D2EHPA—decanol mixture carrier provided a significant synergistic effect in the process. When sulfonated kerosene or sunflower seed oil was used as a diluent, the single extraction efficiency of Ni(II) reached 97.8% and 97.1%, respectively. After three-times extraction, the Ni(II) concentration in the nickel plating effluent decreased to below 1 mg/L. Additionally, in the stripping stage, the stripping efficiency of Ni(II) in the D2EHPA—decanol mixed carrier was larger than that of D2EHPA. Mechanism studies indicate that the polar groups (—OH) from decanol initially break the hydrogen bonds in the D2EHPA dimer structure. Afterwards, van der Waals forces shorten the bond length of P—O to form electron-rich centers of O atoms. Finally, a new P—O—Ni structure is formed through interactions between P—O bond and nickel ions under electrostatic forces.

Directly preparing well-dispersed ultra-hydrophilic NiFeP nanoparticle/Mxene complexes from spent electroless Ni plating solution as efficient hydrogen evolution catalysts

A novel approach is proposed to prepare well-dispersed ultra-hydrophilic NiFeP nanoparticle/Mxene complex by recovering Ni, P, and organic acid from spent electroless Ni-plating solution. The mechanism of NiP-based nanoparticle formation and size regulation during the hydrothermal process is analyzed. Ni2+ chelated with sodium citrate in the electroless Ni plating effluent anchors on the Ti3C2 surface with -OH functional groups by chemical reaction and charge adsorption owing to Mxene surface negativity. The as-prepared ultrafine NiFeP nanodots are connected with alkali-induced Ti3C2 Mxene nanosheets, which possess ultra-hydrophilic performance and rapid H2 bubble desorption behavior. The introduction of alkali-induced Ti3C2 MXene as a substrate controls particle agglomeration in the hydrothermal crystallization process and achieves perfect dispersed distribution of NiFeP nanoparticles to further increase the specific surface area of catalyst. Consequently, the NiFeP/Ti3C2 nanohybrid catalyst exhibits outstanding hydrogen evolution reaction (HER) electrocatalyst performance as a result, with an overpotential of 122 mV at 10 mA cm−2, quick reaction kinetics of 68 mV dec−1, and strong long-term stability over 24 h in 1 M KOH. This research develops a strategy for directly preparing high-value catalyst materialization from spent electroless Ni-plating solution.

Reduction of Chromium in Waste Water From Hard Chrome Plating Processes: A Review

Waste water from hard chrome is considered to be highly toxic due to the presence of chromium ions in hexavalent form and this hexavalent state of chromium is more toxic to animals and humans due to its ability to produce reactive oxygen species in cells. Such heavy metals are considered as carcinogenic to living organisms and hence either reduction of ions to trivalent chromium or removal of ions has to be done before ejecting the waste water into the environment. Many processes for reduction, neutralisation and removal of hexavalent chromium have been investigated and reviewed extensively. In the present review, studies and research carried out for the removal of chromium from waste water of hard chrome plating effluent are summarised. The study was carried out on the aspects such as percentage removal, efficiency and optimum operating conditions in chrome removal and reduction processes.

Systematic examination on adsorption, coagulation activity of clearing nut seed in the removal of copious contaminants from fabric coloring and gold plating effluent

Systematic examination on adsorption, coagulation activity of clearing nut seed in the removal of copious contaminants from fabric coloring and gold plating effluent

Enhanced photoelectrocatalytic oxidation of hypophosphite and simultaneous recovery of metallic nickel via carbon aerogel cathode

Carbon aerogel (CA) cathode was adopted to an undivided-chamber photoelectrocatalytic system with TiO2 nanotube arrays (TNA) photoanode to enhance the oxidation of hypophosphite (H2PO2−) and simultaneous recovery of metallic nickel (Ni). Both the efficiencies of H2PO2− oxidation and Ni recovery were significantly enhanced after replacing Ti or carbon fiber paper cathode with CA cathode. With 1.0 mM H2PO2− and 1.0 mM Ni2+, the ratio of PO43− production increased from ∼41% or ∼54% to ∼100%, and the ratio of Ni recovery increased from ∼20% or ∼ 37% to ∼93% within 180 min at 3.0 V. H2PO2− was finally oxidized to PO43− by •OH radicals, which was speculated to be generated from UV/H2O2 and bound on TNA photoanode. Meanwhile, Ni2+ was eventually electro-reduced to metallic Ni by a two-electron reduction reaction. The efficiencies of H2PO2− oxidation and Ni recovery were favored at higher cell voltage, faintly acid conditions and larger H2PO2− concentration. The stability of this system exhibited that the ratio of PO43− production increased significantly in each cycle, which was attributed to the increase of H2O2 in-situ-generation via CA cathode caused by deposition of metallic Ni. Finally, the treatment of actual electroless nickel plating effluents was demonstrated.

Simultaneous and efficient removal of heavy metal ions and organophosphorus by amino-functionalized cellulose from complex aqueous media

Electroless plating occupies a vital position in the fields of metal anticorrosion while accompanied by a large amount of effluent containing organophosphorus (like phytic acid) and heavy metals ions {like Cu (II) and Ni (II)}. However, it was still remaining great challenges in how to simultaneously remove these organophosphorus and heavy metal ions with simple methods. This work prepared a green, clean and efficient adsorbent amino-functionalized cellulose (AFCA) for simultaneous removal of organophosphorus and metal ions from complex wastewater. Benefitting from its abundant amino groups, AFCA can rapidly remove organophosphorus and metal ions within 10 min. The theoretical maximum adsorption capacities of AFCA could also reach as high as 89.29 mg/g, 79.37 mg/g and 178.57 mg/g, respectively. Most importantly, for the mixed system of organophosphorus and Cu (II), the removal efficiency was increased by 5.66% and 30.23% compared with the individual system, respectively. High simultaneous removal capacity of AFCA was due to the hydrogen bond and electrostatic interactions with organophosphorus and the complexation interactions between abundant amino groups and metal ions. All of these results demonstrate that AFCA has enormous potential for the treatment of actual electroless plating effluents.

Minimizing toxic chlorinated byproducts during electrochemical oxidation of Ni-EDTA: Importance of active chlorine-triggered Fe(II) transition to Fe(IV)

The formation of chlorinated byproducts represents a significant threat to the quality of the effluent treated using electrochemical advanced oxidation processes (EAOPs), thus spurring investigation into alleviating their production. This study presents a new strategy to minimize the release of chlorinated intermediates during the electrochemical oxidation of Ni-EDTA by establishing a dual mixed metal oxide (MMO)/Fe anode system. The results indicate that the dual-anode system achieved a substantially higher rate (0.141 min−1) of Ni-EDTA destruction and accordingly allowed a more pronounced removal of aqueous Ni (from 39.85 to 0.63 mg L−1) after alkaline precipitation, compared with its single MMO anode (0.017 min−1 of Ni-EDTA removal, with 14.38 mg L−1 Ni remaining) and single Fe anode (insignificant Ni-EDTA removal, with 38.37 mg L−1 Ni remaining) counterparts. Compared to reactive chlorine species (RCS) produced from the single MMO anode system, Fe(IV) was in situ generated from the dual-anode system and was predominantly responsible for the attenuation of chlorinated byproducts and thus the decrease in the acute toxicity of the treated solution (evaluated using luminescent bacteria). The Fe(IV)-dominated dual-anode system also exhibited superior performance in removing multiple pollutants (including organic ligands, Ni, and phosphite) in the real electroless plating effluent. The findings suggest that the strategy for Fe(II) transition to Fe(IV) by active chlorine paves a new avenue for yielding less chlorinated products with lower toxicity when EAOPs are used to treat chloride-containing organic wastewater.

High-efficiency treatment of electroless nickel plating effluent using core-shell MnFe2O4-C@Al2O3 combined with ozonation: Performance and mechanism

Heterogeneous catalytic ozonation (HCO) has been widely applied for the treatment of wastewater. In order to maintain the structural stability and surface catalytic activity of heterogeneous catalysts during the HCO treatment of electroless nickel plating effluent (ENPE), a MnFe2O4-C@Al2O3 catalyst with a core-shell structure was synthesized. MnFe2O4-C@Al2O3 was characterized and applied in the removal of total nickel (TNi) and organic contaminants from actual ENPE, using a coupled system of HCO combined with a magnetic dithiocarbamate chelating resin (MnFe2O4-C@Al2O3/O3-MDCR). Results show that embedding Al2O3 with C and MnFe2O4 significantly increased the TNi removal efficiency (99.3%), enhanced the O3-utilization efficiency and improved the generation of reactive oxygen species (ROS). The reaction rate (k = 0.7641 min−1) and O3-utilization efficiency established for TNi removal (ΔTNi/ΔO3 =0.221) by the MnFe2O4-C@Al2O3/O3-MDCR system, were 220% and 140% higher than the Al2O3/O3-MDCR system, respectively. Catalytic mechanism analysis demonstrated that surface hydroxyl groups, oxygen vacancy, metals, the carbon surface and its functional groups, can all potentially serve as catalytic active sites, with 1O2 and •OH considered to the predominant ROS. Overall, these findings verify that the synthesized MnFe2O4-C@Al2O3 catalyst possesses excellent catalytic capabilities and outstanding structural stability, making it suitable for practical application in the treatment of wastewater effluent.

Rapid Treatment and Reaction Mechanism of Complexation Plating Effluents by Molybdenum Disulfide/Copper Sulfide+Peroxosulfate Process

AbstractThe removal of complexed heavy metals in complexation plating effluents is always a problem. Here molybdenum disulfide/copper sulfide (MoS2/CuS) composite was synthesized to activate peroxosulfate (PMS) to treat complexation nickel simulated plating effluents. MoS2/CuS showed excellent PMS activation effect. The removal efficiency of 50 ppm Ni‐EDTA by MoS2/CuS+PMS process and Ni‐citrate by MoS2/CuS process reached 99.7 % and 100 % for 20 min treatment, respectively. The excellent performance of MoS2/CuS+PMS process for heavy metal complexes removal is attributed to two ways: oxidative degradation and catalytic decomplexation. Oxidative degradation is to degrade complexing agent into small molecules through .SO4− produced by PMS activated directly by the synergy between MoS2, CuS and Ni‐EDTA. Catalytic decomplexation is to replace Ni2+ in Ni‐EDTA by the metal active sites of MoS2/CuS to release Ni2+ and remove it. These two degradation pathways make the MoS2/CuS+PMS process has excellent removal efficiency. In addition, the MoS2/CuS+PMS process eliminates the dependence of the Fenton reaction on iron‐based reagents and avoids the production of iron sludge precipitation. These findings provide new insights for the development of metal sulfide activating PMS to treat complexation plating effluents.

Simultaneous and efficient removal of organic Ni and Cu complexes from electroless plating effluent using integrated catalytic ozonation and chelating precipitation process in a continuous pilot-scale system

In the industrial electroless metal plating process, efficient removal of organic-Ni and -Cu complexes from electroless plating effluent (EPE) remains a huge challenge. In this study, a novel and feasible process of heterogeneous catalytic ozonation combined with heavy metal chelation is proposed for the effective removal of organic-Ni and -Cu complexes from EPE. The method was evaluated in a continuous pilot-scale system (CPSS). Results show that the adoption of synchronous bi-directional flow enhanced the removal of total Ni and Cu. Under optimal conditions, the total Ni and Cu in the effluent decreased to 0.1 and 0.3 mg L−1, respectively, meeting the Chinese discharge standard requirements. The CPSS indicated that efficient removal of total Ni and Cu (>95%) was consistently achieved for 300 days using the proposed process. Mechanistic analysis demonstrated that ethylenediamine tetraacetic acid-Ni (EDTA-Ni) and citrate-Cu (CA-Cu) were the main complexes present in EPE. Furthermore, there were 10 transformation products and their related pathways were also identified. The decomplexation of EDTA-Ni was found to be difficult, with its final products principally existing in the complexed states, while CA-Cu was readily broken down, releasing Cu (II) that can be easily chelated. Overall, these findings provide valuable and novel insights into the removal of organic-Ni and -Cu, supporting the practical application of the proposed process in advanced EPE treatment and other industrial wastewater treatment systems.

Utilization of copper plating effluents in the degradation of the dye Sanodure Green in the presence of H2O2

Oxidative degradation of metal complex dye Sanodure Green (SG) in the presence of H2O2 and nanostructured catalyst CuO prepared from copper plating effluents has been investigated. The activity of the CuO catalyst in the oxidative degradation reaction depended on the SG concentration, reaction time and temperature. The reaction followed a pseudo-first order kinetic model, and the rate constant was highly dependent on the increase in temperature, but only slightly on the SG concentration. Thermodynamic studies have shown that the degradation reaction of SG is endothermic. The use of copper plating effluents for the preparation of nanostructured catalyst CuO makes it possible to avoid the accumulation of difficult-to-recycle copper oxide sludge formed during effluent neutralization, and to manage copper plating and aluminum dyeing effluents more economically.

Sorption enhancement of nickel(II) from wastewater by ZIF-8 modified with poly (sodium 4-styrenesulfonate): Mechanism and kinetic study

Effective removal of toxic metal Ni(II) from wastewater is essential to water safety and human health. Although zeolitic imidazolate framework-8 (ZIF-8) has demonstrated outstanding selective removal of Ni(II) in high-salinity wastewater, the practical applications of ZIF-8 are mainly limited by low active sites utilization, slow adsorption kinetics and poor reusability. In this study, we prepared a novel negatively charged poly (sodium 4-styrenesulfonate) (PSS)-modified ZIF-8 adsorbent, ZIF-8@PSS (12 h), which increased the adsorption rate of Ni(II) (kinetic constant k = 0.0299 g mg−1 min−1) by nearly 10 times and the adsorption capacity (329.58 mg/g) by 1.6 times compared to pristine ZIF-8 (k = 0.0021 g mg−1 min−1). ZIF-8@PSS (12 h) (0.5 g/L) could quickly decrease Ni(II) (C0 = 1.0 mg/L) to 0.1 mg/L (discharged standard) in 25 min, while 600 min for ZIF-8. Batch experiments and characterization analyses revealed PSS can improve particle dispersion, increase active sites utilization, and strengthen Ni(II) diffusion kinetics, thereby enhancing the adsorption of Ni(II). Among them, the increase in active sites utilization of ZIF-8 contributes 83.3% to capacity improvement, while the –SO3− on PSS is 16.7%. Furthermore, the enhancements of adsorption kinetics and capacity were also applicable to other heavy metals (e.g., Cu2+, Pb2+, Cr3+, Cd2+). Column experiments using real nickel plating effluent shown that 1 g ZIF-8@PSS (12 h) could produce ~3675 mL of clean water before breakthrough (Ni2+ < 0.1 mg/L). Moreover, a specific nickel chelator, dimethylglyoxime was used to regenerate the exhausted adsorbent and showed an insignificant capacity loss after four cycles. This study indicates the potential of ZIF-8@PSS (12 h) to remove Ni(II) from nickel plating effluent.

Characterizing fluorescence fingerprints of different types of metal plating wastewater by fluorescence excitation-emission matrix

To prevent the illegal discharge of metal plating wastewater (MPW), it is necessary to explore a monitoring method that could achieve the identification of MPW in natural water bodies. Fluorescence excitation-emission matrix-parallel factor (EEM-PARAFAC) analysis might be a promising tool for the detection of MPW. However, before conducting the practical monitoring, the apparent fluorescence features of different kinds of MPW must be first understood. In this study, six types of MPW (576 samples) from ten metal plating plants were collected and their fluorescence fingerprints (FFs) were characterized by EEM-PARAFAC analysis. Results showed that pretreatment wastewater (PTW), copper-contained electroplating wastewater (Cu-EPW), nickel-contained electroplating wastewater (Ni-EPW), copper-contained electroless wastewater (Cu-ELW), nickel-contained electroless wastewater (Ni-ELW), and metal plating effluent (MPE) presented one, three, one, one, two, and three types of FFs, respectively. Among them, three individual fluorescent components were identified in Ni-EPW and two were decomposed in other kinds of MPW. Owing to the discrepancies of production processes, electroplating additives, wastewater treatment techniques, and management levels, different metal plating plants owned different FFs. By spectral comparison, the tyrosine-like components in PTW and Ni-ELW might derived from some phenolic and benzenesulfonic acidic compounds. Fluorescent component similarity analysis indicated that EEM-PARAFAC technique could distinguish the raw and treated MPW. This study not only constructed the first FF database for MPW, but also provided valuable guidance for their practical monitoring in aquatic environment.