Metals recovery from dust derived from recycling line of waste printed circuit boards

Jian

ACS Sustainable Chem. Eng.

et al. 2019

Printed circuit board (PCB) waste contains a high concentration of copper (Cu) leftover from the processing. Another, alkali reduction (AR) wastewater, is considerably produced with a main component of 1,4-benzenedicarboxylic acid (H2BDC) in textile manufacturing. For the sake of environmental sustainability, it is of great significance to recover useful waste sources for reforming into valuable materials. Herein, in this study, for the first time, we report a facile pathway to produce a Cu-based metal–organic framework (CuBDC) in a quantitative yield of 75.45% synthesized by completely using the leaching solutions of PCB and AR wastewater as precursors instead of commercial chemicals. Under a simple stirring condition at room temperature, the as-obtained CuBDC from the wastewater exhibits typical laminar shapes of pure CuBDC crystals. In addition, the wastewater derived CuBDC products were examined with crystalline phase purity, porosity, coordination chemistry, and functional groups. Notably, these characteristics accord well with the concept of high-purity CuBDC. Moreover, the optimal conditions for CuBDC fabrication from PCB and AR wastewater were designed. Lastly, CuBDC from the recycled sources showed high adsorption capacity (5.75 cm3·g–1) and ideal selectivity (10.85) toward CO2 for CO2/CH4, which is unexpectedly outperforming the pure CuBDC. Also in terms of materials cost, the economic feasibility was evaluated. Overall, this work offers a green synthesis pathway for the preparation of sustainable CuBDC by using PCB and AR wastewater.

Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Recyclable Printed Circuit Boards and Alkali Reduction Wastewater: Approach to a Sustainable Copper-Based Metal–Organic Framework

Jian

ACS Sustainable Chem. Eng.

et al. 2019

Curr. Appl. Sci. Technol.

“…Nowadays, Thailand has become one of the world's dumping grounds for e-waste due to its low labor costs and weak environmental laws on waste management [3][4][5]. Huge amounts of ewaste have been smuggled into the country via trading in second-hand goods or plastic waste since the Chinese government enacted a ban on the import of scrap and waste products [6].…”

Section: Introductionmentioning

confidence: 99%

Size Distributions of Inhalable Particulate Matter and Particle-bound Heavy Metals and Their Potential Occupational Health Risk Related to Informal E-waste Recycling in Thailand

Keawhanu

Sukonthamut

Suriyawong

et al. 2022

Concentrations and size distributions of atmospheric particulates and particulate-bound heavy metals in different inhalable fractions were studied in working areas during manual dismantling, thermal cutting and cable sheath burning activities. The particulate samples were collected on quartz fiber filters using an eight-stage cascade impactor with flow rate of 28.3 l min-1. Mass concentrations of the particles were measured in each size fraction. Heavy metals bound on the particles were extracted with acid digestion and then analyzed using Atomic Absorption Spectrophotometer. Risk assessment of worker exposure to the particles was determined. The results indicated that the concentrations of ultrafine (dae < 0.43 μm), fine (0.43 < dae < 2.1 μm) and coarse (2.1 < dae < 10 μm) particles were in the ranges of 14.49-62.04, 57.51-120.26 and 153.26–646.99 μg m−3 during manual dismantling, 363.41-1,011.95, 2,105.40-4,899.11 and 1,698.54-7,075.61 μg m−3 during thermal cutting and 364.73-1,694.72, 1,953.33-4,431.41 and 1,385.97-6,126.13 μg m−3 during cable sheath burning, respectively. The concentrations of PM2.1 and PM10 released from these activities did not exceed the OSHA PEL threshold limits. Heavy metals adsorbed on the particles (Fe, Cr, Zn, Cu, Pb, Mn) detected during manual dismantling did not exceed the TWA standard. Concentrations of Cr and Pb during cable sheath burning highly exceeded the standards whereas Pb concentrations during thermal cutting slightly exceeded the standard. The heavy metals released from these recycling activities were more enriched on coarse mode than fine mode. Inhalation exposure to Cr, Pb and Mn posed a potential health risk to the workers.

“…Adequate decommissioning could convert this waste into source of income due to the high economic value of gold, palladium, silver, and copper, among others metals. 4,5 Adequate recycling of the e-waste including WPCBs will prevent environmental pollution and the recovery and recycling of valuable metals. Several methods such as mechanical processes for size reduction, 5−8 concentration via reverse flotation, 9 froth flotation, 10 and fluidization, 11,12 have been proposed by governments and research institutions.…”

Section: Introductionmentioning

confidence: 99%

Copper and Antimony Recovery from Electronic Waste by Hydrometallurgical and Electrochemical Techniques

et al. 2020

A strategy for the efficient recovery of highly pure copper and antimony metals from electronic waste (e-waste) was implemented by the combination of hydrometallurgical and electrochemical processes. The focus is on copper recovery as the main component in the leached solution, whereas the antimony recovery process was established as a purification step in order to achieve a highly pure copper deposit. The strategy includes mechanical methods to reduce the size of the wasted printed circuit boards to enhance the efficiency of antimony and copper lixiviation via ferric chloride in acidic media (0.5 M HCl) followed by an electrowinning process. In order to establish the best parameters for copper electrowinning, the leached solution was characterized by cyclic voltammetry and cathodic polarization. Then, an electrochemical reactor with a rotating cylinder electrode was used to evaluate the copper concentration decay, the cathodic current efficiency, the specific energy consumption, and mass-transfer coefficient. Furthermore, antimony was recovered via precipitation by a pH modification in accordance with the Pourbaix diagram. Under this methodology, two valuable products from the e-waste were recovered: a 96 wt % pure copper deposit and 81 wt % pure antimony precipitate. The strategy for recovery of other metal ions, such as lead, present in the e-waste at high concentrations will be reported in further works.