A Review on Chemical versus Microbial Leaching of Electronic Wastes with Emphasis on Base Metal Dissolution

There is a growing interest in electronic wastes (e-wastes) recycling for metal recovery because the fast depletion of worldwide reserves for primary resources is gradually becoming a matter of concern. E-wastes contain metals with a concentration higher than that present in the primary ores, which renders them as an apt resource for metal recovery. Owing to such aspects, research is progressing well to address several issues related to e-waste recycling for metal recovery through both chemical and biological routes. Base metals, for example, Cu, Ni, Zn, Al, etc., can be easily leached out through the typical chemical (with higher kinetics) and microbial (with eco-friendly benefits) routes under ambient temperature conditions in contrast to other metals. This feature makes them the most suitable candidates to be targeted primarily for metal leaching from these waste streams. Hence, the current piece of review aims at providing updated information pertinent to e-waste recycling through chemical and microbial treatment methods. Individual process routes are compared and reviewed with focus on non-ferrous metal leaching (with particular emphasis on base metals dissolution) from some selected e-waste streams. Future outlooks are discussed on the suitability of these two important extractive metallurgical routes for e-waste recycling at a scale-up level along with concluding remarks.

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The Potential Production of the Bioactive Compound Pinene Using Whey Permeate

Processes ◽

10.3390/pr8030263 ◽

2020 ◽

Vol 8 (3) ◽

pp. 263 ◽

Cited By ~ 1

Author(s):

Derrick Risner ◽

Maria L. Marco ◽

Sara A. Pace ◽

Edward S. Spang

Keyword(s):

Scale Up ◽

Oxygen Demand ◽

Bioactive Compound ◽

Waste Streams ◽

Significant Cost ◽

Whey Permeate ◽

Low Concentrations ◽

Additional Processing ◽

Plant Metabolite ◽

Secondary Plant Metabolite

Pinene is a secondary plant metabolite that has functional properties as a flavor additive as well as potential cognitive health benefits. Although pinene is present in low concentrations in several plants, it is possible to engineer microorganisms to produce pinene. However, feedstock cost is currently limiting the industrial scale-up of microbial pinene production. One potential solution is to leverage waste streams such as whey permeate as an alternative to expensive feedstocks. Whey permeate is a sterile-filtered dairy effluent that contains 4.5% weight/weight lactose, and it must be processed or disposed of due its high biochemical oxygen demand, often at significant cost to the producer. Approximately 180 million m3 of whey is produced annually in the U.S., and only half of this quantity receives additional processing for the recovery of lactose. Given that organisms such as recombinant Escherichia coli grow on untreated whey permeate, there is an opportunity for dairy producers to microbially produce pinene and reduce the biological oxygen demand of whey permeate via microbial lactose consumption. The process would convert a waste stream into a valuable coproduct. This review examines the current approaches for microbial pinene production, and the suitability of whey permeate as a medium for microbial pinene production.

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Advancements in the treatment and processing of electronic waste with sustainability: a review of metal extraction and recovery technologies

Green Chemistry ◽

10.1039/c8gc03688h ◽

2019 ◽

Vol 21 (5) ◽

pp. 919-936 ◽

Cited By ~ 52

Author(s):

Emily Hsu ◽

Katayun Barmak ◽

Alan C. West ◽

Ah-Hyung A. Park

Keyword(s):

Green Chemistry ◽

Electronic Waste ◽

Waste Recycling ◽

Metal Recovery ◽

Metal Extraction ◽

Current Status

This review highlights the current status of e-waste recycling and provides insights on metal recovery from e-waste via green chemistry.

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The recent trend of e-waste recycling and rare metal recovery in Japan

Waste Management and The Environment VII ◽

10.2495/wm140011 ◽

2014 ◽

Cited By ~ 6

Author(s):

H. Itoh

Keyword(s):

Recent Trend ◽

Rare Metal ◽

Waste Recycling ◽

Metal Recovery

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Characterizations on the Effect of Processing of Polymers Blend with Petroleum Coke (Part I)

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.795.644 ◽

2013 ◽

Vol 795 ◽

pp. 644-648

Author(s):

Syed Bakar Sharifah Shahnaz ◽

Rita Khanna ◽

Sahajwalla Veena ◽

Hussin Kamarudin ◽

N.Z. Noimam ◽

...

Keyword(s):

Petroleum Coke ◽

Emerging Economies ◽

Degradation Process ◽

Waste Recycling ◽

Chemical Recycling ◽

Waste Streams ◽

Polymer Waste ◽

The Past ◽

Global Demand ◽

Interfacial Behaviour

Global demand for plastics has grown significantly over the past decades, and will continue to expand with rising income levels in emerging economies; a number of approaches have been used to recycle polymer waste. While chemical recycling is one of the key methods used as it recovers and reuses the polymer in high-end product; new avenues for waste recycling need to be developed. In-depth interfacial behaviour investigation was carried out to study interactions between polymers and petroleum coke (PC). Polypropylene (PP), polyethylene (PE) and polystyrene (PS) polymers are three major polymers that abundantly found in waste streams were chosen and their properties and the effect of petroleum coke presence on the degradation process of polymer have been characterized. The polymer was mixed and homogenized prior pyrolysis up to 600C. The residues yield after pyrolysis was collected and analyzed.

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A Green, Scalable, One-Minute Synthesis of Benzimidazoles

Synlett ◽

10.1055/s-0039-1690797 ◽

2020 ◽

Vol 31 (06) ◽

pp. 547-552 ◽

Cited By ~ 3

Author(s):

Vijayaragavan Elumalai ◽

Jørn H. Hansen

Keyword(s):

Reaction Time ◽

Ambient Temperature ◽

Functional Group ◽

Scale Up ◽

Reaction Medium

Herein is reported a substantially improved synthesis of 2-substituted benzimidazoles by condensation of 1,2-diaminoarenes and aldehydes using methanol as the reaction medium. The developed method afforded moderate to excellent yields (33–96%) at ambient temperature, displays high functional group tolerance, is conducted open to air, and requires only one minute reaction time under catalyst- and additive-free conditions. Moreover, the efficient protocol permits scale-up to multi-gram scale synthesis of benzimidazoles and will become a method of choice when constructing such heterocyclic systems.

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Scaling up the chemical treatment of spent oil-in-water emulsions from a non-ferrous metal-processing plant

Hemijska industrija ◽

10.2298/hemind120317055l ◽

2013 ◽

Vol 67 (1) ◽

pp. 59-68 ◽

Cited By ~ 2

Author(s):

Vesna Lazarevic ◽

Ivan Krstic ◽

Miodrag Lazic ◽

Dragisa Savic ◽

Dejan Skala ◽

...

Keyword(s):

Aluminum Sulfate ◽

Scale Up ◽

Ferrous Metal ◽

Hydrated Lime ◽

Operating Conditions ◽

Processing Plant ◽

Water Emulsion ◽

Purification Efficiency ◽

Oil In Water ◽

Metal Processing

The treatment of spent oil-in-water emulsion (SOWE) from a non-ferrous metal-processing plant by using aluminum sulfate and hydrated lime was studied to determine the purification efficiency, to optimize the operating conditions and to scale up the treatment process. The purification efficiency was estimated by comparing the compositions of the SOWE and the processed wastewater. The treatment efficiency does not depend on the type of mineral oil and filter aid. The optimum doses of aluminum sulfate and hydrated lime must be experimentally determined for each batch of SOWEs, but the results obtained at laboratory level are applicable at pilot level. The processed wastewater and the filter cake from the process can be safely disposed into public sewage systems and at municipal waste landfills, respectively. The purification efficiency was higher than 98% with respect to total suspended solids, chemical oxygen demand and oil and grease, and was comparable to the known treatment processes based on coagulation/flocculation followed by sedimentation.

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Effects of Artificial Sweat Formulation and Extraction Temperature on Estimation of the Dermal Bioaccessibility of Potentially Toxic Elements in a Contaminated Soil from an E-Waste Recycling Site

Geosciences ◽

10.3390/geosciences12010031 ◽

2022 ◽

Vol 12 (1) ◽

pp. 31

Author(s):

Oluwaseun H. Anselm ◽

Christine M. Davidson ◽

Aderonke O. Oyeyiola ◽

Temilola O. Oluseyi

Keyword(s):

Ambient Temperature ◽

Contaminated Soil ◽

Toxic Elements ◽

Electronic Waste ◽

Size Fraction ◽

Waste Recycling ◽

Potentially Toxic Elements ◽

Dermal Absorption ◽

Extraction Temperature ◽

Artificial Sweat

Informal recycling of electronic waste leads to soil contamination that can impact human health. To accurately assess exposure to potentially toxic elements (PTE) in soil it is necessary to consider their bioavailability through ingestion, inhalation and dermal contact. However, bioaccessibility tests that estimate dermal absorption following adhesion of contaminated soil particles to skin are not well established. In this study the concentrations of As, Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn were estimated in the <45 µm particle size fraction of a bulk composite soil from an e-waste recycling site using five different artificial sweat formulations. Extractions were performed at temperatures ranging from 17 to 47 °C to investigate the effect of ambient temperature on bioaccessibility. Results obtained using the different artificial sweats were not consistent with one another. In particular, the NIHS 96-10 formulation solubilized larger amounts of analytes (ranging from 6.3 times the next most effective extractant for Cu to 1700 times the next most effective for Pb). There was a general increase in release of PTE with increasing temperature, except for As. Although trends varied between analytes and formulations, this highlights the need to consider ambient temperature when estimating dermal bioaccessibility of PTE in soil.

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E-Waste Recycling by Electrostatic Separation

Handbook of Research on Advancements in Environmental Engineering - Advances in Environmental Engineering and Green Technologies ◽

10.4018/978-1-4666-7336-6.ch011 ◽

2015 ◽

pp. 285-317 ◽

Cited By ~ 1

Author(s):

Gordan Bedeković

Keyword(s):

Copper Content ◽

Short Review ◽

Waste Recycling ◽

Product Complexity ◽

Waste Streams ◽

Electrostatic Separation ◽

Separation Processes ◽

Cathode Tube ◽

Mechanical Separation

This chapter discusses the problem of Waste Electric and Electronic Equipment (WEEE) as one of the largest growing waste streams globally, the influence of the product complexity and liberation in separation, and the basics of electrostatic separation. A very short review of mechanical separation processes is given and research conducted on one fraction of CRT TV set is presented. A CRT TV set fraction with higher copper content consists of yokes of a cathode tube, cables, connectors, and wires, which were tested by electrostatic separation method. The aim of this research is to evaluate the effectiveness of electrostatic separation, to determine and rank the influence of separator operating parameters, and to set models for assessment of the concentration quality and recovery of metals. The results show that it is possible to achieve a high quality of concentrates (metal content from 77 to 100%), while recovery varies greatly (from 10 to 99%).

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If it ain’t broke, don’t fix it? Commission efforts to manage the definitions of waste, recycling and recovery, and to switch from a waste streams to a materials approach

elni Review ◽

10.46850/elni.2006.004 ◽

2006 ◽

pp. 18-22

Author(s):

Geert van Calster

Keyword(s):

Waste Recycling ◽

Waste Streams ◽

Proper Definition ◽

Definition Of ◽

The Eu

Discussion on the EU definitions of ‘waste’, as well as ‘recovery’ and ‘disposal’ of waste have been, to paraphrase a standing expression, plentiful and hard on each other’s heels. Ever since the 1991 amendments to the 1975 framework directive, attempts have been made to disprove the usefulness of the definition of waste, and to question the lack of proper definition of the concepts of recovery and disposal. In order to assess the recently issued Commission Proposal for a (renewed) directive on waste, this contribution reviews first of all, succinctly, the nature and limitations of the ‘old’ (existing) definitions, subsequently it reviews the proposed changes.

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