Assessing leaching potential of Electronic Waste

• By: Mitra S.K ADMIN
• December 26 2023
• No Comments

Abstract:

Electronic waste or E-Waste describes discarded electrical or electronic devices. Informal processing of E-waste in developing countries can lead to adverse human health effects and environmental pollution. The present study deals to assess the leaching ability of metals (namely, Copper, Manganese, Nickel, Lead, Antimony and Zn) from a mobile circuit board in different pH condition of water. It was observed that different metals showed varying leaching potential at various pH. This is of huge interest in making a predictive model of ground water contamination arising from improper disposal of e-wastes. 

Keyword: E-waste, Leaching, Metal

Introduction:

Electronic industry is the world’s largest, innovative and fastest growing industry during the last century which radically changed the people's lifestyle. Although this development has helped the human race, but emerged a new environmental problem called electronic waste (e-waste). The sources of the majority of these can be traced to major developed countries, although there is an increasing contribution from rapidly developing countries like China and India. E-waste is increasing drastically, with a growth rate of 20-25% annually. Many factors contribute to this surge in e-waste. These include the short lifecycle of equipment, low recycling, and the continuous upgrading of electronic equipment as affluent societies demand the latest technology. E-waste has been described as one of most difficult classes of waste to manage due to a constant change in its features and specificities. The inappropriate handling of e-waste is unsafe for both human health and the environment, discharging heavy metals and persistent organics.

Since 2010, the volume of e-waste generated globally has been steadily rising. By 2019, approximately 53.6 million metric tons was produced. This was an increase of 44.4 million metric tons in just five years. Of this, just 17.4 percent was documented to be collected and properly recycled.

According to a 2020 report by the Central Pollution Control Board, India generated 1,014,961 tonnes of e-waste in FY 2019-2020 – up 32% from FY 2018-2019. Of this, the report found that only 3.6% and 10% were actually collected in the country in 2018 and 2019, respectively.

Effects of e-waste on the Environment

• Emissions of toxic fumes and gases causing air pollution.
• Toxic chemicals from e-waste enter the “soil-crop-food pathway”.
• These are biodegradable and cause soil and ground water pollution.
• E-waste dumping yards and nearby places are polluted and cause health hazards.

Effect on Human Body

Materials & Methods:

Mobile circuit board was taken out from old, unusable mobile phones.

All the chemicals and reagents were purchased from Merck, India and were of GR Grade.

Sample preparation: Circuit board was cut into pieces and soaked in different pH conditioned water (pH 5-6, pH 8-9 and pH 7.0). This water was tested for leaching ability of those heavy toxic metals using ICP-OES following standard method.

Results:

1. In neutral water Medium: In neutral water medium, i.e. pH 7.0, it was observed that Ni showed profound leachability peaking at day 14. The results were incorporated in Figure 1.
2. In alkaline water Medium: In alkaline water medium, i.e. pH 8.0-9.0, it was observed that Zn followed by Cu showed profound leachability peaking at day 7. The results were incorporated in Figure 2.
3. In acidic water Medium: In neutral water medium, i.e. pH 5.0-6.0, it was observed that Pb, Zn and Cu showed profound leachability peaking at day 7, whereas Cu continued to peak up to 21 days. The results were incorporated in Figure 3.

Figure 1: Leaching ability of Metals in Neutral Water medium

Figure 2: Leaching ability of Metals in Alkaline Water medium

Figure 3: Leaching ability of Metals in Acid Water medium

Conclusion

• In neutral medium Ni was found to be leached maximum on 14th day. Rest of the metals were absent in initial as well as after 21 days of leaching experiment.
• In acidic medium Pb was found to be leached maximum on 7th day, Zn & Ni on 21st day, Cu on 7th day.
• In alkaline medium Zn & Cu was found to be leached maximum on 7th day. Rest of the metals were absent in initial as well as after 21 days of leaching experiment.

Contributed by : Koustav Shil, Amartya Gupta