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.
The marine coating in the tidal zone is crucial to restoring its protective function in the case of coating defects, mainly due to the structural damage of the coating by the alternation of wet and dry in the tidal zone and the surface damage of the coating by the impact of sand and gravel. Hydrophilic materials such as hydrogel transformed the tidal zone into an entire immersion zone. Due to the complexation of copper, the fouling problem can be effectively reduced. The coating (AAm/Alginate-Ca/Cu-BTA) has excellent mechanical properties (modulus: 200 kPa, toughness 128 J m −2 ) and significant adhesion (138 J m −2 ). Otherwise, herein, simultaneously mechanical tests of hydrogels at different temperatures and excellent mechanical properties (modulus: 160 kPa, toughness 100 J m −2 ) after 7 days of use in alternating dry and wet environments every 6 h are shown. It's proved that the coating has an excellent antifouling and anticorrosion effect. Meanwhile, theoretical study reveals the nature of the weak mechanical properties of hydrogel materials at low temperatures. This work provides an effective strategy for preparing hydrogel coatings with excellent mechanical properties and marine anticorrosion and antifouling. It also proves that hydrogels have broad application prospects in marine tidal zone by excellent water retention performance.
危险品化学品经营许可证（带存储）