The issue of the abundance of waste printed circuit boards (WPCB) is a worldwide dilemma due to the fast upgrading of manufacturing technology and the short life span of electronic devices. Traditional treatment methods are facing the challenge of public concerns since they fail to solve the toxic emission problem as well as the high construction / operation cost. Nevertheless the recycling of WPCB achieved the recovery of the metallic fraction of WPCB; they failed to provide a solution for the non-metallic fraction (NMF) of WPCB and most of them have a negative profit. A lot of studies have been done based of the reuse of the NMF, but majority of them still were proved to be invalid of remedying the cost of metallic faction recycling.

Currently, the chemical composition and framewo...[ Read more ]

The issue of the abundance of waste printed circuit boards (WPCB) is a worldwide dilemma due to the fast upgrading of manufacturing technology and the short life span of electronic devices. Traditional treatment methods are facing the challenge of public concerns since they fail to solve the toxic emission problem as well as the high construction / operation cost. Nevertheless the recycling of WPCB achieved the recovery of the metallic fraction of WPCB; they failed to provide a solution for the non-metallic fraction (NMF) of WPCB and most of them have a negative profit. A lot of studies have been done based of the reuse of the NMF, but majority of them still were proved to be invalid of remedying the cost of metallic faction recycling.

Currently, the chemical composition and framework structure of the NMF imply a possibility of utilizing the NMF as a precursor for aluminosilicate adsorbent production. In this study, the NMF was used as the feedstock of an adsorbent production process and it showed superior heavy metal uptake capacity after the surface functionalization. In the first phase of this study, the reaction parameters of the production process were studied and optimized to provide an optimum condition of material production. The reaction parameters including reaction temperature, impregnation ratio and reaction time were investigated and the results showed that the optimum condition was 300˚C, impregnation ratio of 2 and 1 h reaction time. Further textural properties and surface characterization proved as-prepared sample have the well-developed structure as well as the high density of surface functional group. After that, it is proved that quenching technology is also capable to further improve the surface properties of the material by prevent the unwanted side reaction during the cooling process. The batch adsorption tests proved that quenched sample had even higher heavy metal uptake capacities.

In the second phase of this study, the environmental emission analysis of this process was conducted based on a self-assembled reactor. The mass balance of the reaction reagents, bromide and carbon were established, providing clear pathway and destination of the possible pollution issues this process may emit. Meanwhile, the leaching test was performed to evaluate the stability of this adsorbent. Summarily, the environmental impacts of this process are comparably lower than other current NMF recycling methods and gave a new option for WPCB treatment.

Abbreviations

WEEE: Waste Electrical and Electronic Equipments

WPCB: Waste Printed Circuit Boards

MF: Metallic Fraction of Waste Printed Circuit Boards

NMF: Non-Metallic Fraction of Waste Printed Circuit Boards

BO: Bridging Oxygen Atoms

NBO: Non-Bridging Oxygen Atoms

TBBPA: Tetrabromobisphenol A

BPA: Bisphenol A