Zhenming Xu

Central South University | CSU · School of Metallurgy and Environment

Electronic waste (e-waste) recycling is becoming a global concern owing to its immense quantity, hazardous character and the potential loss of valuable metals. The many processes involved in e-waste recycling stem from a mixture of physicochemical reactions, and understanding the principles of these reactions can lead to more efficient recycling me...

Deep and efficient debromination is a critical step in achieving environmentally friendly recycling and ensuring the sustainability of waste-printed circuit boards (WPCBs) because of their high toxicity and carcinogenicity. To this end, this study used a copper–iron (Cu/Fe) bimetal as a debromination agent to remove bromides from WPCBs using in sit...

Nonmetals in waste printed circuit boards after metal separation containing brominated resin and fiberglass are considered hazardous and low-recoveryvalue e-waste. However, if these nonmetals are not treated or are improperly treated, they can cause serious environmental pollution. Therefore, there is an urgent and significant need to develop an ef...

Rare earth elements (REEs), one of the global key strategic resources, are widely applied in electronic information and national defense, etc. The sharply increasing demand for REEs leads to their overexploitation and environmental pollution. Recycling REEs from their second resources such as waste fluorescent lamps (WFLs) is a win–win strategy for...

With the rise of the new energy vehicle industry represented by Tesla and BYD, the need for lithium-ion batteries (LIBs) grows rapidly. However, owing to the limited service life of LIBs, the large-scale retirement tide of LIBs has come. The recycling of spent LIBs has become an inevitable trend of resource recovery, environmental protection, and s...

Recycling spent lithium-ion batteries (LIBs) is becoming a hot global issue due to the huge amount of scrap, hazardous, and valuable materials associated with end-of-life LIBs. The electrolyte, accounting for 10-15 wt % of spent LIBs, is the most hazardous substance involved in recycling spent LIBs. Meanwhile, the valuable components, especially Li...

The recycling of waste printed circuit boards (WPCBs) has attracted global attention because of their increasingly huge quantity, hazardous character, and high recovery values. There are plenty of reviews about the recycling of baseboards. In addition to basal boards, various and hundreds of electronic components (ECs) are mounted on the surface of...

In recent years, the rapid development of technology has posed significant challenges to the waste management practices of the retired vehicle industry. How to minimize the environmental impact during the recycle process of scrap vehicle has emerged as a prevalent and pressing concern. This study employed statistical analysis and positive matrix fa...

The value of considerable residual energy in waste Li-ion batteries (WLIBs) is always neglected. At present, "this energy" is always wasted during the discharge process of WLIBs. However, if this energy could be reused, it would not only save a lot of energy but also avoid the discharge step of recycling of WLIBs. Unfortunately, the instability of...

Metal recycling from waste printed circuit boards (WPCBs) is crucial for resource sustainability. Electrolysis is promising in simplifying processes, improving recycling efficiency, and reducing consumption, while full knowledge on multi metal fate and response mechanism is indispensable for processing complex metals (Cu-Fe-Sn-Pb-Ni-Ag-Au) from WPC...

Bromine is an important resource that is widely used in medical, automotive, and electronic industries. Waste electronic products containing brominated flame retardants can cause serious secondary pollution, which is why catalytic cracking, adsorption, fixation, separation, and purification have gained significant attention. However, the bromine re...

Multi metal recycling from waste printed circuit boards (WPCBs) is attractive for resource conservation and sustainability. While smelting is commonly adopted to produce polymetallic concentrates from WPCBs, current processes cost oxidation smelting and fire refining followed by electrorefining to deport co-existing base metals and recover copper,...

With the widespread photovoltaic deployment to achieve the net-zero energy goal, the resulting photovoltaic waste draws attention. In China, considerable steps have not been taken for photovoltaic waste management. The lack of relevant scientific information on photovoltaic waste brings difficulties to the establishment of photovoltaic waste regula...

Waste printed circuit boards (WPCBs) are generated increasingly recent years with the rapid replacement of electric and electronic products. Pyrolysis is considered to be a potential environmentally-friendly technology for recovering organic and metal resources from WPCBs. Thermogravimetric analysis and kinetic analysis of WPCBs were carried out in...

The output of waste silicate municipal solid waste represented by waste glass is huge. However, the paint coating which affects the quality of remanufactured silicate products is hazardous waste and difficult to separate from silicate resources. The aim of this study is developing new technology to clean paint coating for a more complete recycling...

The resource utilization of waste glass is mainly divided into two aspects: adding waste glass as a raw material to the production of new glass, and employing it as building materials. Obviously, the resource utilization of waste glass is still in a low value-added stage, which leads to a low recovery rate of waste glass. Thus, how to achieve high...

Chlorofluorocarbons (CFCs), which possess the characteristics of high volatility and destroy ozone layer, are hardly disposed of through traditional methods. With a tightly closed reaction environment and high-temperature water medium, CFCs can react and generate inorganic Cl⁻ and F⁻ under subcritical water conditions, which is very useful to enhan...

Plastics used in electric and electronic products cover a wide range, and contain many additives, such as brominated flame retardant and so on. These compounds and microplastics may be released into environment when the electric and electronic products are obsoleted and recycled. This study explores the characteristics of microplastics and the comp...

Recycling of electronic waste (e-waste) and inevitable pollution under current technology have always been a concern of people. Generation and release of pollutants in the recycling process of e-waste are closely related to processing technology and equipment. In this paper, the pollution characteristics of different functional areas and critical p...

Spent lithium-ion batteries (LIBs) have been one of the fast-growing and largest quantities of solid waste in the world. Spent graphite anode, accounting for 12-21 wt% of batteries, contains metals, binders, toxic, and flammable electrolytes. The efficient recovery of spent graphite is urgently needed for environmental protection and resource susta...

The ever-increasing quantity of spent lithium-ion batteries (LIBs) is both a potential environmental pollutant and a valuable resource. The spent LIBs recycling mainly aimed at the separation of valuable elements. Some issues still exist in these processes such as high energy consumption and complex separation procedures. This study avoided element...

Nowadays, plastic pollution attracts attention, while data on microplastic (MP) emissions to atmosphere from urban mining bases are rarely quantified. In this paper, the emission characteristics of MPs in road fugitive dust from two urban mining bases were studied, the emission factors of MPs from road fugitive dust source were updated, and emissio...

In order to avoid secondary pollution during recovery of brominated resin, additives had been proposed for capturing bromine in high-temperature (700 °C) pyrolysis of brominated resin. However, the capture capacity and mechanism of CaCO3 and activated carbon to the generated micromolecule bromides was still unknown in the low-temperature (300 °C) p...

As a kind of typical veterinary drug, fluoroquinolone antibiotics (FQs) are widely used in the field of livestock and poultry breeding, but these FQs escape to surrounding soil through various pathways, polluting soil through long-term accumulation. Current study proposed a clean technology named thermal desorption to deal with FQs contaminated soi...

In this study, the distribution of precious metals in waste printed circuit boards was investigated and the economic value of recycling was assessed. Contacts of pins, slots, interfaces and the board surface in waste printed circuit boards were analyzed, and three types of precious metals were detected. The content of gold, silver and palladium ran...

High Br-containing polystyrene (PS) plastics are generated in large quantities during the dismantling of waste CRT TVs. Debromination and reuse of Br-containing PS plastics is a critical technical challenge. Here, we demonstrate a method for combining alkaline hydrothermal debromination and co-blending granulation to achieve the regeneration of hig...

Environmental information in recovery of waste plastic in a certificated factory in industrial park in Eastern China is provided in this paper. The process involves raw material storage, washing, closed crushing, closed regeneration, product storage, and waste storage. Particulate matters, heavy metals, polycyclic aromatic hydrocarbons (PAHs), poly...

Aluminum has been playing a significant role in the development of global vehicles light-weighting for mass reduction and energy conservation. Owing to the limited lifespan of automobiles, the huge wave of obsolete automotive aluminum (OAA) has come. China, the country with the largest vehicles ownership in the world, will be facing with the OAA bo...

The service life of glass is limited, leading to a large amount of waste glass generated. The waste glass recycling base, as an essential municipal supporting facility of a sustainable city, has a significant impact on the surrounding ecological environment. This study conducted a comprehensive investigation and analysis of the potential pollutants...

Clean energy technologies are emerging as a major contributor to the total energy supply. Some metals play irreplaceable roles in these technologies. The supply risk of metals used in clean energy technologies is gradually increasing. Hence, it is necessary to investigate the supply risks of these metals worldwide. In this study, a comprehensive as...

For the conservation and sustainable utilization of metallic resources, recovering precious metals from the vast quantity of waste printed circuit boards is an attractive avenue. Bioleaching has been proved as an environment-friendly and suitable recovery technology. However, the limited cyanogenic capability restricts the industrialization of this...

The recovery and reuse of waste brominated resin, which is a typical plastic waste, is troublesome because it contains toxic brominated flame retardants. Conventional pyrolysis of brominated resin was suggested to be an effective approach for debromination. However, conventional pyrolysis caused high energy consumption and high yield of toxic volat...

Precious metal (PM) retrievement from e-waste is of great significance for reducing virgin mining activity and promoting rare resource sustainability. However, current PM recycling methods rely mainly on caustic aqua regia or unstable sulfur-based ligand, which cause severe environmental damage and process inefficiency. Here, we propose an environm...

Waste printed circuit boards are produced greatly due to the wide application of electronic devices, in which non-ferrous metals are valuable resources. Without effective recovery processes, it can cause serious heavy metal pollution. Traditional recover technologies will cost too much energy, materials, manpower together with producing secondary e...

The rapid development of new energy technology leads to explosive growth of lithium-ion batteries (LIBs) industry which greatly alleviates the problems of environmental pollution and energy shortage. However, how to realize resource circulation of critical metals including lithium (Li) and cobalt (Co) becomes the new problem of LIBs industry. This...

Electronic waste (e-waste), as hazardous waste, is a promising secondary resource of precious metals. The extraction of precious metals from e-waste has great environmental and economic benefits. Most of the existing methods have high energy consumption, environmental pollution or low recovery efficiencies. This study proposed the application of gr...

Recycling activity for waste electrical and electronic equipment is always accompanied with leaching solution containing copper. Its selective extraction is of environmental and economic significance, and is beneficial for subsequent resource purification procedure. Compared with techniques such as chemical precipitation and solvent extraction, pot...

How to realize the high value-added utilization of scrap copper from e-waste is a meaningful topic. In the study, an Ohno Continuous Casting (OCC) process is an existing method you applied to purify the copper. Based on the model of diffusion-controlled grain growth kinetics, the redistribution of impurity of tin in the scrap copper were studied un...

The recovery of waste glass is an important issue in the fields of social sustainable development and resource recovery. The removal of organic impurity is the first step in the recovery of waste glass. Currently, desiccation-dissociation technology is advised to remove the organic impurity from waste glass. However, the risks of the organic impuri...

Every year, billions of tons of lignite are burnt to generate electricity, meanwhile generating large amounts of coal fly ash (CFA) that is regarded as an industrial waste. During lignite combustion, arsenic and scarce metals are simultaneously volatilized in the form of oxide into CFA. This study proposed an effective vacuum distillation method to...

With the rapid decrease of high-quality coal reserves, utilization of lignite is already a trend in worldwide. Unlike anthracite, lignite often contains special elements Ge, W, As. When these incineration ashes are reused, some resuspended fine particles will inevitably escape into the air, thereby affecting the surrounding environment. The study a...

With a huge amount of waste liquid crystal displays (LCDs) generated annually, their proper recycling raises continuous concern to realize pollution control (heavy metal and liquid crystal) and resource recovery (indium). However, due to their multi-metallic feature, traditional hydrometallurgy lacks of sufficient selectivity, which makes the recyc...

The main components of waste capacitors are BaTiO3, Ag, Pd, Sn, Ni, Nb, and Pb, which are valuable for recycling. At present the acid leaching is applied to separate metals from capacitors. However, the process is complex and will cause secondary pollution to the environment. In this work, we have broken through the traditional method of only recov...

Polycarbonate/acrylonitrile-butadiene-styrene blends (PC/ABS) has become one of the most common polymer insulation materials as packaging resin in electronics industry, due to its excellent mechanical, flame retardant and insulating properties. Once electronic products are eliminated and discarded, refractory PC/ABS will become a huge obstacle to e...

A targeted extraction technology for recycling lithium from spent lithium transition metal oxides (LTMO) type batteries is developed in this paper. The chlorinating technology with ammonium chloride as the only additive is employed and controlled to selectively extract lithium. High lithium extraction rate with a low selectivity was first obtained...

The recycling of spent lithium-ion batteries (LIBs) has been one of the global environmental concerns due to their huge quantity and hazardous and valuable character. The existing spent LIB processing mainly focuses on element separation, which is usually complex and energy consuming and even causes new environmental issues. This study breaks throu...

The increasingly large stream of e-waste is seriously threatening the environment; meanwhile, global energy shortage is on the rise. Based on the principles of energy regeneration and waste utilization, we introduced a win-win approach to utilize waste capacitors for construction of magnetic and core-shell Z-scheme Nb-Pb-codoped BaTiO3/Ni-Pd@graphi...

Spent lithium-ion batteries (LIBs) recycling has attracted much attention because it is highly favorable to environment protection and sustainable development. Developing a cleaner method for metals extraction can greatly reduce risk of secondary pollution. Chlorinating technology has been proved as an efficient method for metals extraction instead...

Recycling waste multilayer ceramic capacitors (MLCCs) has attracted much attention owing to its rich metal resource and environment pollution. Existing recycling processes have deficiencies in environmental protection, efficiency and metal purity. Capture technology is promising with advantages of efficient enrichment and less pollution, which was...

Antibiotics are commonly used in livestock and poultry breeding along with organic arsenic. Through long-term accumulation, they can enter into the surrounding soil through various pathways and contaminate the soil. In this paper, tetracycline antibiotics (TCs) and roxarsone (ROX) contaminated soil were used as the representatives of the two kinds...

Electronic waste, as hazardous waste, contains a large amount of metals, which is of great recovery value. However, they are difficult to separate due to wide variety and complex distribution. Most of current recycling methods are environmentally-unfriendly or complicated. In this study, a simple, efficient and green approach for metals separation...

Waste multilayer ceramic capacitors (MLCCs) are important secondary resource containing silver and palladium. Current methods of directly recovering precious metals from waste MLCCs have certain deficiencies in terms of environmental protection, recovery efficiency and purity. Capture technology has advantages of high enrichment efficiency and less...

Polyethylene glycol terephthalate and ethylene-vinyl acetate copolymer are applied as packaging materials in solar cells. Abundant polyethylene glycol terephthalate and ethylene-vinyl acetate copolymer were produced with the production of waste solar cells. To our knowledge, few technologies have been reported about the disposal of polyethylene gly...

From environmental security and resource recovery viewpoint, hydrothermal technology was adopted to recycle Ag, As, and Ga from waste LEDs in present study. Waste LEDs packaging materials (Polyphthalamide (PPA), epoxy resin, and brominated flame retardant (BFR)), which are difficult to degrade under normal conditions, can be effectively decomposed...

Ball-milling technology is adopted for the debromination of nonmetallic particles of waste printed circuit boards. During the ball-milling process, too short ball-milling time causes insufficient debromination. Excessive ball-milling leads to the waste of resources and the destruction of the main structure of nonmetallic particles resin, unfavorabl...

Polybrominated diphenyl ethers (PBDEs) are released from the recycling process of PBDE-containing waste printed circuit board (WPCB), but studies on the mechanism of PBDE emission and migration are limited. In this study, PBDE concentrations in particulate matter (PM), dust, and fumes collected in a pilot-scale workshop for the WPCB de-soldering pr...

The emission characteristics of respirable particulate matter (PM10), and polybrominated diphenyl ether (PBDE) size distribution, gas-particle partitioning and occupational exposure in two e-waste recycling workshops (manual and thermal dismantling workshop: ManuDW and TherDW) were investigated. The PM10 mass concentration was higher but the number...

In order to ensure the performance and safety of electronic products, a large number of polymeric insulation resins are used as housing materials. When electronic products are discarded as e-waste, these resins containing organobromine compounds and antimony trioxide as flame retardants are difficult to be disposed of by traditional recycling metho...

Increased generation of spent lithium-ion batteries (LIBs) has driven the exploration of new methods for reusing and/or recycling LiCoO2 cathode materials. Herein, an electrochemical relithiation method was proposed to directly regenerate LiCoO2 cathode materials using the waste LixCoO2 electrode as a base. It was shown that Li+ was successfully in...

Cobalt is an increasingly important strategic metal with the emerging of clean energy technologies. China is a resource scarcity country but the world’s largest cobalt consumer. It is of great strategic significance to study the application and current status of cobalt resources for the sustainable development of China’s economy. The objective of t...