Comparison of the environmental impact of the conventional nickel electroplating and the new nickel electroplating

Abstract

Purpose To comply with the effluent regulation of boron, replacement of boric acid with citric acid in a nickel electroplating bath is proposed. Although the bath avoids the discharge of boron, it increases the discharge of nickel owing to the chelating effect of citric acid, which disturbs the wastewater treatment. To balance this trade-off, the environmental impacts of a traditional nickel plating process (the Watts bath) and the citrate bath must be compared by life cycle assessment. Methods The life cycle impact assessment method was LIME2. To estimate the trade-off between boron and nickel discharge into wastewater, the characterization and damage factors on human toxicity and ecotoxicity were calculated. The processes were then compared using data from actual processes. The functional unit was Bplating per 1-kg part.Ĥ owever, the plating efficiency depends on the type, shape, and surface area of the part. The data of the citrate bath were modeled. In the modeling, the amounts of nickel chloride and nickel sulfate in the citrate bath were based on the Watts bath. Results and discussion In comparison with other chemicals, the calculated characterization and damage factors of boron and nickel were found to be reasonable. The integration results revealed that the citrate bath exerted greater environmental impact than the Watts bath. Although the Watts bath involved more environmentally damaging processes than the citrate bath, the sum of these impacts was much smaller than the impact of effluent from the citrate bath. Moreover, the environmental impact of effluent can be significantly reduced by flocculants, with almost no additional environmental impact incurred by the increased sludge. Conclusions The newly developed citrate plating bath exerts higher environmental impact than the traditional Watts bath because the environmental impacts of the release of nickel chelated with citric acid exceed the reduced boron emissions. Therefore, there is a trade-off between the two methods. When installing the citrate bath, the wastewater treatment must be altered to reduce the nickel emissions.

Lithiophilic 3D Copper‐Based Magnetic Current Collector for Lithium‐Free Anode to Realize Deep Lithium Deposition

“…To further verify the role of the magnetic field for the deep deposition within the substrate, nickel was used instead of lithium to simulate the electroplating process on CF. [ 47 ] Figure S1a in the Supporting Information shows the simple schematic diagram of electroplating, where the red line on the left of CF shows that only this area is in contact with the electrolyte, and the arrow indicates the direction of movement of ions into the CF. The cross‐sectional digital photo images for the CF after Ni deposition are shown in Figure S1b,c in the Supporting Information.…”

Ni-P coatings electroplating - A review, Part I: Pure Ni-P alloy

“…Presence of boron in the bath waste is nonetheless reported to be harmful for the environment. Since the enforcement of Water Pollution Control Act in Japan [59] the imposed national minimum effluent standards have greatly influenced the electroplat- ing industry. Thus, it became necessary to find more environmentally friendly solutions for the electrodeposition of nickel and its alloys.…”

“…When it comes to the environmental impact exerted by the electroplating process from either of the two baths: the one containing boric or the other containing citric acid, findings are quite contradictory. Takuma et al [59] applied a life cycle assessment method to demarcate the extent of their influence in terms of human toxicity and ecotoxicity. Results indicated that the newly developed citrate plating bath exerts higher environmental impact compared to the traditional Watts electrolyte, this owing to the release of nickel chelated with citric acid whose harmful influence overshadows the benefit of reduced boron emissions achieved by substituting boric acid in the electroplating bath.…”

Pretreatment with fine bubbles for effective zinc ion precipitation and removal from zinc electroplating wastewater

“…Therefore, the environmental impact of these chemicals needs to be evaluated and reduced through suitable treatment of industrial wastewater. [ 1 ] Heavy metals, such as zinc, copper, and chromium, are harmful to the environment and human body [ 2,3 ] ; therefore, the concentrations of these metals in effluents are strictly regulated. [ 4 ] In Japan, the effluent standard value for zinc is 2 mg/L.…”