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Sustainable Algal Bioremediation for Heavy Metals in Wastewater

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A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (31 December 2021) | Viewed by 15751

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Special Issue Editor

Dr. Hussein Znad

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Guest Editor

WA School of Mines: Minerals, Energy and Chemical Engineering, Curtin University, GPO Box U1987, Perth, WA 6845, Australia
Interests: microalgae and algal environmental applications; wastewater/air pollution treatment; ad/bio-sorbent development for heavy and rare earth metals; optical functionalized nanomaterials for detecting and removing metals from aqueous solution; photo/catalyst development; advanced oxidation processes (photo-Fenton, ozone, UV/solar, ZnO/TiO2 photocatalysis); biowaste-based biodiesel production; bio-hydrogen production from wastewater; modelling, optimization, and scale-up of photo/bioreactors

Special Issue Information

Dear Colleagues,

You are cordially invited to contribute original research papers or reviews to this Special Issue of Molecules, which will report on sustainable sources of algal biomass and seaweeds for the bioremediation of heavy metals in wastewater. The bioremediation of heavy-metal-contaminated effluents represents a major challenge for the wastewater treatment industry. Under optimized conditions, algal biomass can sequestrate up to hundreds of milligrams of metal per gram of biomass; this high biosorption capacity has been receiving industrial interest. However, producing an economical and sustainable algal bioremediation process for heavy metal removal will rely heavily on the appropriate algal biomass, supply, reuse, and metal recovery. This Issue primarily focuses on algal biomass pre-treatment, immobilization, and factors affecting biosorption capacity, such as wastewater quality, initial metal ion concentration, biomass concentration, initial pH, time, temperature, and interference of multiple metal ions. Submissions related to the optimization of low-cost algal biomass for high bioremediation potential will be encouraged.

Dr. Hussein Znad
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Molecules is an international peer-reviewed open access semimonthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2700 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

Algal biomass
Bioremediation
Biosorption capacity
Heavy metals
Wastewater

Published Papers (4 papers)

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Research

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14 pages, 1446 KiB

Open AccessArticle

Autochthonous Arthrospira platensis Gomont Driven Nickel (Ni) Phycoremediation from Cooking Oil Industrial Effluent

by Isha Shakoor, Aisha Nazir, Sonal Chaudhry, Qurat-ul-Ain, Firdaus-e-Bareen and Sergio C. Capareda

Molecules 2022, 27(16), 5353; https://doi.org/10.3390/molecules27165353 - 22 Aug 2022

Cited by 1 | Viewed by 1432

Abstract

Nickel (Ni) leftovers arise from both catalyst application interventions and Ni alloy piping of the cooking oil industry (COI) being wasted as pollutants of freshwater bodies via discharged effluent. The current study assessed one of the indigenously feasible Ni removal systems comprising autochthonous Arthrospira platensis Gomont (AP)-driven Ni phycoremediation cells (NPCs). After screening AP for hyperaccumulation in the Ni spiked solution, AP was transferred to the NPCs. Propagation of the AP inoculum was proportionate to the pollution load drop of COI with 22.97 and 55.07% drops in the biochemical (BOD) and chemical oxygen demand (COD), respectively. With the 0.11 bioconcentration factor, there was an uptake of 14.24 g mineral with 16.22% Ni removal and a 36.35 desorption ratio. The experimental data closely fitted with the Langmuir and Freundlich isotherms, respectively. The study concluded that A. platensis could be taken for treatment of Ni-loaded industrial effluents at the microcosmic level. Full article

(This article belongs to the Special Issue Sustainable Algal Bioremediation for Heavy Metals in Wastewater)

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12 pages, 1543 KiB

Open AccessArticle

Sustainability Evaluation of Immobilized Acid-Adapted Microalgal Technology in Acid Mine Drainage Remediation following Emergy and Carbon Footprint Analysis

by Kuppan Praveen, Sudharsanam Abinandan, Kadiyala Venkateswarlu and Mallavarapu Megharaj

Molecules 2022, 27(3), 1015; https://doi.org/10.3390/molecules27031015 - 02 Feb 2022

Cited by 6 | Viewed by 1780

Abstract

Sustainability evaluation of wastewater treatment helps to reduce greenhouse gas emissions, as it emphasizes the development of green technologies and optimum resource use rather than the end-of-pipe treatment. The conventional approaches for treating acid mine drainages (AMDs) are efficient; however, they need enormous amounts of energy, making them less sustainable and causing greater environmental concern. We recently demonstrated the potential of immobilized acid-adapted microalgal technology for AMD remediation. Here, this novel approach has been evaluated following emergy and carbon footprint analysis for its sustainability in AMD treatment. Our results showed that imported energy inputs contributed significantly (>90%) to the overall emergy and were much lower than in passive and active treatment systems. The microalgal treatment required 2–15 times more renewable inputs than the other two treatment systems. Additionally, the emergy indices indicated higher environmental loading ratio and lower per cent renewability, suggesting the need for adequate renewable inputs in the immobilized microalgal system. The emergy yield ratio for biodiesel production from the microalgal biomass after AMD treatment was >1.0, which indicates a better emergy return on total emergy spent. Based on greenhouse gas emissions, carbon footprint analysis (CFA), was performed using default emission factors, in accordance with the IPCC standards and the National Greenhouse Energy Reporting (NGER) program of Australia. Interestingly, CFA of acid-adapted microalgal technology revealed significant greenhouse gas emissions due to usage of various construction materials as per IPCC, while SCOPE 2 emissions from purchased electricity were evident as per NGER. Our findings indicate that the immobilized microalgal technology is highly sustainable in AMD treatment, and its potential could be realized further by including solar energy into the overall treatment system. Full article

(This article belongs to the Special Issue Sustainable Algal Bioremediation for Heavy Metals in Wastewater)

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Review

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35 pages, 12142 KiB

Open AccessReview

Is Genetic Engineering a Route to Enhance Microalgae-Mediated Bioremediation of Heavy Metal-Containing Effluents?

by Saeed Ranjbar and Francisco Xavier Malcata

Molecules 2022, 27(5), 1473; https://doi.org/10.3390/molecules27051473 - 22 Feb 2022

Cited by 15 | Viewed by 3820

Abstract

Contamination of the biosphere by heavy metals has been rising, due to accelerated anthropogenic activities, and is nowadays, a matter of serious global concern. Removal of such inorganic pollutants from aquatic environments via biological processes has earned great popularity, for its cost-effectiveness and high efficiency, compared to conventional physicochemical methods. Among candidate organisms, microalgae offer several competitive advantages; phycoremediation has even been claimed as the next generation of wastewater treatment technologies. Furthermore, integration of microalgae-mediated wastewater treatment and bioenergy production adds favorably to the economic feasibility of the former process—with energy security coming along with environmental sustainability. However, poor biomass productivity under abiotic stress conditions has hindered the large-scale deployment of microalgae. Recent advances encompassing molecular tools for genome editing, together with the advent of multiomics technologies and computational approaches, have permitted the design of tailor-made microalgal cell factories, which encompass multiple beneficial traits, while circumventing those associated with the bioaccumulation of unfavorable chemicals. Previous studies unfolded several routes through which genetic engineering-mediated improvements appear feasible (encompassing sequestration/uptake capacity and specificity for heavy metals); they can be categorized as metal transportation, chelation, or biotransformation, with regulation of metal- and oxidative stress response, as well as cell surface engineering playing a crucial role therein. This review covers the state-of-the-art metal stress mitigation mechanisms prevalent in microalgae, and discusses putative and tested metabolic engineering approaches, aimed at further improvement of those biological processes. Finally, current research gaps and future prospects arising from use of transgenic microalgae for heavy metal phycoremediation are reviewed. Full article

(This article belongs to the Special Issue Sustainable Algal Bioremediation for Heavy Metals in Wastewater)

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21 pages, 1009 KiB

Open AccessReview

The Utilization of Algae and Seaweed Biomass for Bioremediation of Heavy Metal-Contaminated Wastewater

by Hussein Znad, Md. Rabiul Awual and Sri Martini

Molecules 2022, 27(4), 1275; https://doi.org/10.3390/molecules27041275 - 14 Feb 2022

Cited by 86 | Viewed by 7913

Abstract

The presence of heavy metals in water bodies is linked to the increasing number of industries and populations. This has serious consequences for the quality of human health and the environment. In accordance with this issue, water and wastewater treatment technologies including ion exchange, chemical extraction, and hydrolysis should be conducted as a first water purification stage. However, the sequestration of these toxic substances tends to be expensive, especially for large scale treatment methods that require tedious control and have limited efficiency. Therefore, adsorption methods using adsorbents derived from biomass represent a promising alternative due to their great efficiency and abundance. Algal and seaweed biomass has appeared as a sustainable solution for environmentally friendly adsorbent production. This review further discusses recent developments in the use of algal and seaweed biomass as potential sorbent for heavy metal bioremediation. In addition, relevant aspects like metal toxicity, adsorption mechanism, and parameters affecting the completion of adsorption process are also highlighted. Overall, the critical conclusion drawn is that algae and seaweed biomass can be used to sustainably eliminate heavy metals from wastewater. Full article

(This article belongs to the Special Issue Sustainable Algal Bioremediation for Heavy Metals in Wastewater)

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