scholarly journals ASSESSMENT OF BIOAVAILABILITY OF HEAVY METALS AFTER VERMICOMPOSTING IN THE PRESENCE OF ELECTRONIC WASTE

2015 ◽  
Vol 39 (6) ◽  
pp. 1786-1795 ◽  
Author(s):  
Odilaine Inácio de Carvalho Damasceno ◽  
César Reis ◽  
Efraim Lázaro Reis ◽  
Carlos Roberto Bellato ◽  
Paulo Henrique Fidêncio
Keyword(s):  
Heavy Metals ◽  
Printed Circuit Boards ◽  
Environmental Concern ◽  
Electronic Waste ◽  
High Mobility ◽  
Residual Fraction ◽  
Small Scale ◽  
Circuit Boards ◽  
Metal Levels ◽  
Exchangeable Fraction

ABSTRACT Heavy metals contained in electronic waste, if discarded improperly, can become bioavailable after vermicomposting, posing a risk to the environment. Small-scale vermicomposting experiments were carried out with printed circuit boards (PCBs) to investigate the migration of heavy metals (Cu, Pb, Zn, Ni, and Sn) to the final compost, as well as the mobility and bioavailability of these metals. High total levels of Pb, Sn and Cu in samples of manure with electronic waste (MEW) and vegetables with electronic waste (VEW) were detected. Based on the initial metal levels in the PCBs and their concentration in the resulting compost, the order of migration of these metals to the MEW and VEW samples was Sn (23.1 %)>Pb (18.4 %)>Ni (4.63 %)>Zn (0.46 %)>Cu (0.14 %) and Sn (24.3 %)>Pb (23.6 %)>Ni (11.33 %)>Zn (1.76 %)>Cu (0.60 %), respectively. Mobility and bioavailability of these metals in the compost were evaluated by three-stage sequential extraction, where F1 was the exchangeable fraction, F2 the organic fraction and F3 the residual fraction. The bioavailability factor (BF) was calculated by the ratio of the sum of fractions F1 and F2 divided by the total sum of the fractions (F1 + F2 + F3). The highest bioavailability factor (BF = 0.92) was found for Pb, the heavy metal considered the greatest environmental concern in this study, indicating the high mobility and the possibility of becoming bioavailable of this metal.

scholarly journals Food Waste-Assisted Metal Extraction from Printed Circuit Boards: The Aspergillus niger Route

2021 ◽  
Vol 9 (5) ◽  
pp. 895
Author(s):  
Carlotta Alias ◽  
Daniela Bulgari ◽  
Fabjola Bilo ◽  
Laura Borgese ◽  
Alessandra Gianoncelli ◽  
...  
Keyword(s):  
Solid State ◽  
Aspergillus Niger ◽  
Food Waste ◽  
Solid State Fermentation ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Metal Extraction ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards

A low-energy paradigm was adopted for sustainable, affordable, and effective urban waste valorization. Here a new, eco-designed, solid-state fermentation process is presented to obtain some useful bio-products by recycling of different wastes. Urban food waste and scraps from trimmings were used as a substrate for the production of citric acid (CA) by solid state fermentation of Aspergillus niger NRRL 334, with a yield of 20.50 mg of CA per gram of substrate. The acid solution was used to extract metals from waste printed circuit boards (WPCBs), one of the most common electronic waste. The leaching activity of the biological solution is comparable to a commercial CA one. Sn and Fe were the most leached metals (404.09 and 67.99 mg/L, respectively), followed by Ni and Zn (4.55 and 1.92 mg/L) without any pre-treatments as usually performed. Commercial CA extracted Fe more efficiently than the organic one (123.46 vs. 67.99 mg/L); vice versa, biological organic CA recovered Ni better than commercial CA (4.55 vs. 1.54 mg/L). This is the first approach that allows the extraction of metals from WPCBs through CA produced by A. niger directly grown on waste material without any sugar supplement. This “green” process could be an alternative for the recovery of valuable metals such as Fe, Pb, and Ni from electronic waste.

scholarly journals Analysis of the treatment of plastic from electrical and electronic waste in the Republic of Serbia and the testing of the recycling potential of non-metallic fractions of printed circuit boards

2017 ◽  
Vol 71 (3) ◽  
pp. 271-279
Author(s):  
Aleksandra Vucinic ◽  
Zeljko Kamberovic ◽  
Milisav Ranitovic ◽  
Tihomir Kovacevic ◽  
Irena Najcevic
Keyword(s):  
Chemical Composition ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Mechanical Methods ◽  
The Republic ◽  
Electrical And Electronic Waste ◽  
Metallic Fractions

This paper presents the analysis of the quantity of plastic and waste printed circuit boards obtained after the mechanical treatment of electrical and electronic waste (E-waste) in the Republic of Serbia, as well as the recycling of non-metallic fractions of waste printed circuit boards. The aim is to analyze the obtained recycled material and recommendation for possible application of recyclables. The data on the quantities and treatment of plastics and printed circuit boards obtained after the mechanical treatment of WEEE, were gained through questionnaires sent to the operators who treat this type of waste. The results of the questionnaire analysis showed that in 2014 the dismantling of E-waste isolated 1,870.95 t of plastic and 499.85 t of printed circuit boards. In the Republic of Serbia, E-waste recycling is performed exclusively by using mechanical methods. Mechanical methods consist of primary crushing and separation of the materials which have a utility value as secondary raw materials, from the components and materials that have hazardous properties. Respect to that, the recycling of printed circuit boards using some of the metallurgical processes with the aim of extracting copper, precious metals and non-metallic fraction is completely absent, and the circuit boards are exported as a whole. Given the number of printed circuit boards obtained by E-waste dismantling, and the fact that from an economic point of view, hydrometallurgical methods are very suitable technological solutions in the case of a smaller capacity, there is a possibility for establishing the facilities in the Republic of Serbia for the hydrometallurgical treatment that could be used for metals extraction, and non-metallic fractions, which also have their own value. Printed circuit boards granulate obtained after the mechanical pretreatment and the selective removal of metals by hydrometallurgical processes was used for the testing of the recycling potential. Granulometric analysis as well analysis of chemical composition of obtained fractions was performed. Subsequently, the manual classification of different types of polymeric material contained in the granulate was made, and both the apparent specific gravity and the chemical composition of the classified types of polymeric materials were determined. Chemical composition of granulate was determined by X-Ray Fluorescence (XRF) using Thermo Scientific Niton XL 3t, while the identification of residual polymers was determined by the FTIR (Fourier Transform Infrared Spectroscopy) method on the Bomen MB 100 device in range 4000 to 400 cm?1. Based on the results of this study, it can be concluded that after the hydrometallurgical treatment of printed circuit boards, and the separation of metals that have the highest value, the residual non-metallic fraction have the utility value and can be used for various purposes, such as developing new polymer materials for technical purposes that have been investigated by many researchers and mentioned in this article.

scholarly journals Recycling Waste Circuit Board Efficiently and Environmentally Friendly through Small-Molecule Assisted Dissolution

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Zhiqiang Chen ◽  
Meng Yang ◽  
Qian Shi ◽  
Xiao Kuang ◽  
H. Jerry Qi ◽  
...  
Keyword(s):  
Small Molecule ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Environmentally Friendly ◽  
Circuit Board ◽  
Circuit Boards ◽  
Thermosetting Polymers ◽  
Damage Repair ◽  
Wide Range ◽  
Low Efficiency

AbstractWith the increasing amount of electronic waste (e-waste) generated globally, it is an enormous challenge to recycle printed circuit boards (PCBs) efficiently and environmentally friendly. However, conventional recycling technologies have low efficiency and require tough treatment such as high temperature (>200 °C) and high pressure. In this paper, a small-molecule assisted approach based on dynamic reaction was proposed to dissolve thermosetting polymers containing ester groups and recycle electronic components from PCBs. This effective approach operates below 200 °C and the polymer could be dissolved in a short time. It has a remarkable ability to recycle a wide range of commercial PCBs, including boards made of typical anhydride epoxy or polyester substrate. Besides, it is environmentally friendly as even the recycling solution could be reused multiple times. In addition, the wasted solution after recycling could be used for board bonding and damage repair. This work also demonstrates the advantage of using polymers containing ester groups as the PCB substrate in consideration of eco-friendly and efficient recycling.

scholarly journals Recovery of Metals from Electronic Waste by Reduction Melting Method

2015 ◽  
pp. 49-55
Author(s):  
Pornpaitoon Laosombatthawee ◽  
Dawan Wiwattanadate ◽  
Sujarinee Kotchawattana
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Circuit Boards ◽  
Optimal Conditions ◽  
Metallic Lead ◽  
Melting Method ◽  
Lead Recovery ◽  
Preliminary Study ◽  
Micro Analysis

This study investigates application of the reduction melting method to recover metals fromelectronic wastes. The study began with determination of the optimal conditions for metal recovery from cathode ray tube (CRT) glass by melting under various conditions. The reco-very of metallic lead and lead oxide (PbO) remaining in the glass residues for each set of melting condition were compared. It was found that the optimal condition for metallic Pb recovery from the CRT glass was melting the glass at 1200oC for 1 hand then soaking at precipitation temperature of 500oC for 1-2 h. Under these conditions, recovery rates of metallic lead from CRT glass reached up to 85-89%. The optimal conditions identified in this preliminary study were then used to recover metals from a mixture of CRT glass and printed circuit boards (PCBs), as a proxy for electronic waste. Electron Probe Micro Analysis (EPMA)characterization indicated two categories of metal deposits; the first being metallic lead (Pb) and the second as a mixture of copper (Cu), tin (Sn), and antimony (Sb). The study also confirmedthat incorporation of PCB did not affect lead recovery from CRT glass.

Recycling of Printed Circuit Boards by Direct Molding Technology

2019 ◽  
Author(s):  
F. Quadrini ◽  
D. Bellisario ◽  
G. M. Tedde ◽  
L. Santo
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Flexural Modulus ◽  
Circuit Boards ◽  
Low Friction ◽  
Environmentally Conscious ◽  
Printed Circuit ◽  
Waste Pcbs ◽  
Pure Compression ◽  
Organic Fractions

Abstract The recovery and reuse of printed circuit boards (PCBs) is becoming crucial in the management of electronic waste that is undergoing an exponential increase. In this study, a simple and eco-friendly process for recycling waste PCBs is discussed. In particular, composite panels were produced by reusing 100% of waste PCBs without the addition of any additive or virgin material. After a two-step grinding process, ground PCB was used to mold panels by direct molding which is pure compression molding without material sorting. Results were very promising in terms of process feasibility and part performances. Molded samples had density about 1.45 g/cm3, flexural modulus and flexural about 3 GPa and 16 MPa, respectively. A smooth surface with low friction coefficient was obtained for the recycled panels. The study shows that despite the presence of metal and other non-metal non-organic fractions, waste PCBs can be re-processed in profitable and environmentally conscious way without the addition of any bonding agent or additive. The recycling technology can be extended to the reuse of the non-metallic fraction only, after separation and recovery of metals.

Isolation and characterization of copper leaching microbes from sanitary landfills for copper bioleaching of waste printed circuit boards

2021 ◽  
Author(s):  
Muhammad Syafiq Razali ◽  
Fatimah Azizah Riyadi ◽  
Fazrena Nadia Md Ak ◽  
Muhamad Ali Muhammad Yuzir ◽  
Nor’azizi Othman ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Acid Leaching ◽  
Metal Extraction ◽  
Soluble Form ◽  
Circuit Boards ◽  
Printed Circuit ◽  
Waste Printed Circuit Boards ◽  
Isolation And Characterization

Abstract Electronic waste has been the fastest increasing waste generated globally and predicted to surpass 111 million tons per year by the end of 2050. The amount of e-waste is a concern not just due to its volume, but also due to its high composition of heavy metal elements, which has leads to increased development of urban mining in terms of heavy metal extraction. One common method of extraction, i.e., acid leaching, is known for its harmful residual leachate, in which can have a high impact on the environment. This focuses on the alternative leaching techniques known as bioleaching, which take advantages of microbial activity in mobilization of metal into a more soluble form. Strains from sanitary landfill soil were isolated in acidic media and identified as Bacillus sp. strain SE, Lysinibacillus sp. strain SE2, Bacillus sp. strain S1A, and Oryzobacter sp. strain SC. Among the isolated stains, the identified strain Oryzobacter sp. strain SC was able to extract up to 23.36 ppm copper from waste printed circuit boards using a two-step bioleaching process, confirming the ability of the strain to perform bioleaching of copper from e-waste.

scholarly journals Simulation of printed circuit boards recycling process

2019 ◽  
Vol 292 ◽  
pp. 01040
Author(s):  
Dagmar Janacova ◽  
Jan Pitel ◽  
Vladimir Vasek ◽  
Pavel Mokrejs ◽  
Miluse Viteckova ◽  
...  
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Temperature Fields ◽  
Circuit Boards ◽  
Heating And Cooling ◽  
Physical Problems ◽  
Initial Stage ◽  
New Criteria ◽  
Difficult Issue

This paper focused on the modeling of ecological PCB. Due to the high increase in the production of electronic waste, which contains a whole range of usable components, it is necessary to recycle it. About the study of the issue, we have proposed a solution for the separation of conductive paths from plastic and taking into account the legislative approaches and taking into account the existing methods of PCB separation, the composition, and production of PCBs and also the binders used in PCBs. We used the knowledge of process engineering to design a mathematical description of temperature fields in PCB and stress. To a great extent, we have devoted ourselves to the simulation experiments of PCB heating and cooling and the determination of temperature fields and stress due to temperature, cyclic mechanical stresses due to temperature. The simulation is performed in the Pro/ENGINEER and COMSOL Multiphysics® software environments, because of the possibility of solving multi-physical problems. Outputs from computer simulations are the initial stage for designing an eco-friendly way of recycling PCBs. In the future, we will focus on the more difficult issue of recycling multilayer PCBs. The development of new criteria for PCB recycling has opened new possibilities of treatment for used materials.

Studies on leaching characteristics of electronic waste for metal recovery using inorganic and organic acids and base

2020 ◽  
pp. 0734242X2093192
Author(s):  
Debarati Das ◽  
Siddhartha Mukherjee ◽  
Mahua Ghosh Chaudhuri
Keyword(s):  
Printed Circuit Boards ◽  
Electronic Waste ◽  
Circuit Boards ◽  
X Ray Diffraction ◽  
Aqua Regia ◽  
X Ray ◽  
Printed Circuit ◽  
Inorganic Acids ◽  
Acid And Base ◽  
Before And After

In this paper, we report leaching of precious and scattered metals such as gold (Au), copper (Cu), nickel (Ni), zinc (Zn), iron (Fe), and lead (Pb) from printed circuit boards of scrap mobile phones by hydrometallurgical process using inorganic acid, organic acid and base. The amount of metals leached by different leachants are quantified using atomic absorption spectroscopy. Among various inorganic acids, aqua regia (mixture of nitric acid (HNO3) and hydrochloric acid) is found to be the strongest leachant for most of the metals such as Zn (2.04 wt %), Fe (17.90 wt %), Ni (0.66 wt %), Pb (5.86 wt %) and Au (0.04 wt %). The basic leachant, ammonium thiosulphate is found to be very effective in leaching of Au (0.03125 wt %). The dissolution of Cu in HNO3 gives the highest amount of Cu in the solvent, that is, ∼ 7.52 wt %. The metallic phases present in the electronic waste before and after leaching are identified by X-ray diffraction analysis. The microscopic structure has been studied using a scanning electron microscope which depicts erosion of the structure after leaching.

scholarly journals Decomposition of LCD screen inverter by pyrolysis

2019 ◽  
Vol 116 ◽  
pp. 00024
Author(s):  
Agnieszka Gurgul ◽  
Włodzimierz Szczepaniak ◽  
Monika Zabłocka-Malicka
Keyword(s):  
Printed Circuit Boards ◽  
Pyrolysis Temperature ◽  
Technology Development ◽  
Electronic Waste ◽  
Complex Structure ◽  
Circuit Boards ◽  
Gas Emission ◽  
Waste Sample ◽  
Printed Circuit ◽  
Waste Pcbs

PCBs (Printed Circuit Boards) are important parts of electronic equipment and their use increases with technology development. Recycling of waste PCBs is challenging due to their complex structure and receives wide concerns as the amount of this type of waste is growing rapidly. In the article, the experiment of pyrolysis carried out with electronic waste sample was presented. The material employed in the present work was inverter of the LCD screen that it the example of the multilayer PCB. The correlation between pyrolysis temperature and gas emission from the system, which is associated with epoxy resin decomposition, is presented in the article.

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