Chemical looping gasification using Nickel-containing electroplating sludge and dyeing sludge as oxygen carrier

Transformation behavior of heavy metal during Co-thermal treatment of hazardous waste incineration fly ash and slag/electroplating sludge

In this study, the behavior of heavy metal transformation during the co-thermal treatment of hazardous waste incineration fly ash (HWIFA) and Fe-containing hazardous waste (including hazardous waste incineration bottom slag (HWIBS) and electroplating sludge (ES)) was investigated. The findings demonstrated that such a treatment effectively reduced the static leaching toxicity of Cr and Pb. Moreover, when the treatment temperature exceeded 1000 °C, the co-thermal treated sample exhibited low concentrations of dynamically leached Cr, Pb, and Zn, indicating that these heavy metals were successful detoxified. Thermodynamic analyses and phase transformation results suggested that the formation of spinel and the gradual disappearance of chromium dioxide in the presence of Fe-containing hazardous wastes contributed to the solidification of chromium. Additionally, the efficient detoxification of Pb and Zn was attributed to their volatilization and entry into the liquid phase during the co-thermal treatment process. Therefore, this study sets an excellent example of the co-thermal treatment of hazardous wastes and the control of heavy metal pollution during the treatment process.

Approaches for electroplating sludge treatment and disposal technology: Reduction, pretreatment and reuse

Electroplating sludge (ES) has become an obstacle to the sustainable development of the electroplating industry. Electroplating sludge has a large storage capacity, with a high concentration of soluble pollutants (heavy metals), which has great potential to harm the local ecosystems and human health. Although much research has been done in this area, there seems to be no mature and stable solution. Therefore, the latest technologies for the reduction, pretreatment and reuse of electroplating sludge are emphatically introduced based on the analysis of the characteristics of electroplating sludge and its impact on the ecological environment. The factors hindering the treatment and disposal of electroplating sludge are pointed out, and reasonable and feasible suggestions to solve this problem are proposed. The solidification and removal mechanism of heavy metals in electroplating sludge is emphatically analyzed. The physicochemical and separation processes of heavy metals, as well as thermal treatment technique are discussed. Finally, it is proposed to establish a database of the physicochemical properties and elemental content of electroplating sludge to achieve its systematic treatment and digestion. We hope that this paper can help solve the problem of electroplating sludge and promote the sustainable development of the electroplating industry.

Structured electroplating sludge derived membrane for one-step removal of oil, metal ions, and anions from oil/water emulsions

The effective simultaneous treatment of hazardous waste sludge and complex oil/water emulsions in one way is urgently desired but still a challenging issue. Herein, this work for the first time presents a green and efficient strategy to fabricate an electroplating sludge (ES) derived multifunctional self-supporting membrane for the one-step removal of emulsified oils, soluble metal ions, and anions in complex oily wastewater. Due to low cost of ES and sustainability of the solvent selected in fabrication process, the large-scale application of the membrane is easily to promote. The assembled hierarchical nanostructure endowed robust underwater superoleophobicity of the membrane even under various corrosive aqueous environments, as well as excellent ultra-low oil adhesion and anti-oil-fouling performance, without chemical modification. Significantly, the multifunctional membrane possessed desirable simultaneous separation efficiency for five typical oil-in-water emulsions (>99.4%, high oil/water selective wettability), including crude oil-in-water emulsion with high viscosity (>99.6%), Cu²⁺ (>96.1%, surface complexation and ionic exchange), and Cl^- (>92.7%, electrostatic attraction). Therefore, this green, low-cost, and multifunctional membrane not only allows the large-scale resource utilization of hazardous waste sludge, but also effectively solves the problems of complex oily wastewater purification.

A review on fabricating functional materials by electroplating sludge: process characteristics and outlook

As the end product of the electroplating industry, electroplating sludge (ES) has a huge annual output and an abundant heavy metal (HM). The effective disposal of ES is attracting increasing attention. Currently, the widely used ES disposal methods (e.g. landfill and incineration) make it difficult to effectively control of HMs and synchronously utilise metal resources, leading to a waste of metal resources, HMs migration, and potential harm to the environment and human health. Therefore, techniques to limit HMs release into the environment and promote the efficient utilisation of metal resources contained within ES are of great interest. Based on these requirements, material reuse is a great potential means of ES management. This review presents an overview of the process flows, principles and feasibilities of the methods employed for the material reuse of ES. Several approaches have been investigated to date, including (1) additions in building materials, (2) application in pigment production, and (3) production of special functional materials. However, these three methods vary in their treatment scales, property requirements, ability to control HMs, and degree of utilisation of metal resources in ES. Currently, the safety of products and costs are not paid enough attention, and the large-scale disposal of HMs is not concordant with the effective management of HMs. Accordingly, this study proposes a holistic sustainable materialised reuse pattern of ES, which combines the scale and efficiency of sludge disposal and pays attention to the safety of products and the cost of transformation process for commercial application.

Toxic waste sludge derived hierarchical porous adsorbent for efficient phosphate removal

Global effective treatment of phosphorus crisis and toxic waste sludge in one way is urgently needed but still insufficient due to single function, environmental damage, and complicated fabrication process. Herein, we proposed a facile, low-cost, and sustainable strategy to fabricate NiAl layered double oxides/nickel-containing sludge (LDOs/NCS) adsorbent using toxic NCS as raw material via two-step method including hydrothermal process and calcination. The as-designed hierarchical porous adsorbent with large specific surface area and pore volume exhibited excellent adsorption properties towards phosphate. Langmuir adsorption model exhibited the best fit to the experimental data, which illustrated that the adsorption process was dominated by monolayer adsorption. Moreover, even in various double anions systems or in a wide pH range environment (2-12), the as-designed LDOs/NCS still maintained relatively stable adsorption capacity. A possible adsorption mechanism involving surface complexation and electrostatic interactions was investigated. Besides, the LDOs/NCS also displayed admirable durability and reusability. Therefore, this waste-control-waste strategy not only simultaneously addresses phosphorus crisis treatment and toxic NCS management, but also could be potentially extended towards rational design of other metals-containing sludge derived functional materials.