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The use of algae-based green synthesis of metal oxide nanoparticles (MONPs) for bioremediation is an environmentally friendly and cost-effective alternative to conventional approaches. Algal-mediated synthesis offers several benefits over other biogenic processes, such as plants, bacteria, and fungi, including ease of synthesis, scalability, and rapid synthesis. Algae are readily available in nature, nontoxic, and can produce various types of metal oxide nanoparticles. This approach could significantly accelerate the development of novel algae-nanomaterials with improved properties and performance, leading to more efficient and cost-effective bioremediation of pollutants from water solutions, seawater, and industrial effluent. This review focuses on the biogenic fabrication of metal oxide nanoparticles based on aquatic plants (microalgae and seaweeds) due to their many advantages and attractive applications in pollutant remediation from aqueous solutions. Additionally, photocatalysis is highlighted as a promising tool for the remediation of industrial effluents due to its efficacy, ease of use, quick oxidation, cost-effectiveness, and reduced synthesis of harmful byproducts. [ABSTRACT FROM AUTHOR]

Metallic glasses (MGs) with a unique atomic structure have been widely used in the catalytic degradation of organic pollutants in the recent years. Fe78Si9B13 MGs exhibited excellent catalytic performance for the degradation of oily wastewater in a Fenton-like system for the first time. The oil removal and chemical oxygen demand (COD) removal from the oily wastewater were 72.67% and 70.18% within 60 min, respectively. Quenching experiments were performed to verify the production of active hydroxyl radicals (·OH) by activating hydrogen peroxide (H2O2). The formation of ·OH species can significantly contribute to the degradation reaction of oily wastewater. Fe78Si9B13 MG ribbons were highly efficient materials that exhibited superior reactivity towards H2O2 activation in oily wastewater treatment. The study revealed the catalytic capability of metallic glasses, presenting extensive prospects of their applications in oily wastewater treatment. [ABSTRACT FROM AUTHOR]

Low-temperature plasma (LTP) technology has been successfully used to treat persistent organic pollutants in water. Efforts have been devoted to combine catalysts and LTP to improve the degradation efficiency of pollutants and energy utilization efficiency. Herein, industrial solid waste red mud as a novel catalyst was added to an LTP system to treat crystalline violet (CV) wastewater. The energy yield at 50% CV decomposition and TOC after a 30 min reaction by the plasma treatment, red mud adsorption, and red mud/plasma treatment were compared. The effects of the main operating parameters, such as red mud dosing amount, initial pH, discharge voltage, and initial concentration of CV, on the removal efficiency of CV were investigated. The best degradation of CV was achieved with a red mud dosage of 2 g, a neutral environment, and a discharge voltage of 22 kV. When the red mud was recycled three times, the removal efficiency decreased a little in the red mud/plasma system. Hydroxyl radical plays an important role in the treatment of CV. The red mud was characterized by BET, SEM, XRD, and FT-IR, and the structure of the red mud was not greatly affected after being used in the red mud/plasma system. [ABSTRACT FROM AUTHOR]

Over the past few decades, enzyme-based green and sustainable chemistry has attracted extensive research attention, which provides a promising alternative to the conventional treatment methods of recalcitrant micropollutants. However, enzyme denaturation and stability loss remain critical challenges for its potential applications in industrial wastewater treatment. In this study, laccase from Trametes versicolor (laccase T.) was cross-linked immobilized by ultraporous alumina (UPA) for the sustainable biodegradation of Remazol Brilliant Blue R (RBBR). Through sequential use of an aminosilane coupling agent (3-aminopropyl)triethoxysilane (APTES) and bifunctional cross-linker glutaraldehyde (GA), the synthesized biocatalysts showed better immobilization performances (about 4-fold to physical adsorption). The GA concentration considerably affected the laccase T. cross-linking degree, while the GA post-treatment protocol showed the highest laccase T. immobilization yield with lower activity recovery. Moreover, the biocatalyst stabilities including pH stability, thermal stability, storage stability, and reusability were also studied. Tolerance to broader pH and temperature ranges, better storage stability, good reusability of laccase T. cross-linked UPA(γ) biocatalysts, and their continuous RBRR biodegradation efficiency highlight the potentials of enzyme-based inorganic materials in industrial wastewater treatment, which can broaden our understanding of their practical applications in environmental fields. [ABSTRACT FROM AUTHOR]

Two-dimensional compounds with nanostructural features are attracting attention from researchers worldwide. Their multitude of applications in various fields and vast potential for future technology advancements are successively increasing the research progress. Wastewater treatment and preventing dangerous substances from entering the environment have become important aspects due to the increasing environmental awareness, and increasing consumer demands have resulted in the appearance of new, often nonbiodegradable compounds. In this review, we focus on using the most promising 2D materials, such as MXenes, Bi2WO6, and MOFs, as catalysts in the modification of the Fenton process to degrade nonbiodegradable compounds. We analyze the efficiency of the process, its toxicity, previous environmental applications, and the stability and reusability of the catalyst. We also discuss the catalyst's mechanisms of action. Collectively, this work provides insight into the possibility of implementing 2D material-based catalysts for industrial and urban wastewater treatment. [ABSTRACT FROM AUTHOR]

Industries such as mining, cokemaking, (petro)chemical and electroplating produce effluents that contain free cyanide (fCN = HCN + CN−). Currently, fCN is mainly removed by (physico)chemical methods or by biotreatment with activated sludge. Cyanide hydratases (CynHs) (EC 4.2.1.66), which convert fCN to the much less toxic formamide, have been considered for a mild approach to wastewater decyanation. However, few data are available to evaluate the application potential of CynHs. In this study, we used a new CynH from Exidia glandulosa (protein KZV92691.1 designated NitEg by us), which was overproduced in Escherichia coli. The purified NitEg was highly active for fCN with 784 U/mg protein, kcat 927/s and kcat/KM 42/s/mM. It exhibited optimal activities at pH approximately 6–9 and 40–45 °C. It was quite stable in this pH range, and retained approximately 40% activity at 37 °C after 1 day. Silver and copper ions (1 mM) decreased its activity by 30–40%. The removal of 98–100% fCN was achieved for 0.6–100 mM fCN. Moreover, thiocyanate, sulfide, ammonia or phenol added in amounts typical of industrial effluents did not significantly reduce the fCN conversion, while electroplating effluents may need to be diluted due to high fCN and metal content. The ease of preparation of NitEg, its high specific activity, robustness and long shelf life make it a promising biocatalyst for the detoxification of fCN. [ABSTRACT FROM AUTHOR]

This work studied the removal of phenol from industrial effluents through catalytic ozonation in the presence of granular activated carbon in a continuous fixed-bed reactor. Phenol was chosen as model pollutant because of its environmental impact and high toxicity. Based on the evolution of total organic carbon (TOC) and phenol concentration, a kinetic model was proposed to study the effect of the operational variables on the combined adsorption–oxidation (Ad/Ox) process. The proposed three-phase model expressed the oxidation phenomena in the liquid and the adsorption and oxidation on the surface of the granular activated carbon in the form of two kinetic constants, k1 and k2 respectively. The interpretation of the constants allow to study the benefits and behaviour of the use of activated carbon during the ozonisation process under different conditions affecting adsorption, oxidation, and mass transfer. Additionally, the calculated kinetic parameters helped to explain the observed changes in treatment efficiency. The results showed that phenol would be completely removed at an effective contact time of 3.71 min, operating at an alkaline pH of 11.0 and an ozone gas concentration of 19.0 mg L−1. Under these conditions, a 97.0% decrease in the initial total organic carbon was observed. [ABSTRACT FROM AUTHOR]

The petroleum industry is one of the most rapidly developing industries and is projected to grow faster in the coming years. The recent environmental activities and global requirements for cleaner methods are pushing the petroleum refining industries for the use of green techniques and industrial wastewater treatment. Petroleum industry wastewater contains a broad diversity of contaminants such as petroleum hydrocarbons, oil and grease, phenol, ammonia, sulfides, and other organic composites, etc. All of these compounds within discharged water from the petroleum industry exist in an extremely complicated form, which is unsafe for the environment. Conventional treatment systems treating refinery wastewater have shown major drawbacks including low efficiency, high capital and operating cost, and sensitivity to low biodegradability and toxicity. The advanced oxidation process (AOP) method is one of the methods applied for petroleum refinery wastewater treatment. The objective of this work is to review the current application of AOP technologies in the treatment of petroleum industry wastewater. The petroleum wastewater treatment using AOP methods includes Fenton and photo-Fenton, H2O2/UV, photocatalysis, ozonation, and biological processes. This review reports that the treatment efficiencies strongly depend on the chosen AOP type, the physical and chemical properties of target contaminants, and the operating conditions. It is reported that other mechanisms, as well as hydroxyl radical oxidation, might occur throughout the AOP treatment and donate to the decrease in target contaminants. Mainly, the recent advances in the AOP treatment of petroleum wastewater are discussed. Moreover, the review identifies scientific literature on knowledge gaps, and future research ways are provided to assess the effects of these technologies in the treatment of petroleum wastewater. [ABSTRACT FROM AUTHOR]

Background: There is a need for more effective methods of industrial wastewater treatment. Methods: Cosmetic wastewater was collected and subjected to H2O2/Fe3O4/Fe2O3/Fe0 and UV/H2O2/Fe3O4/Fe2O3/Fe0 process treatment. Results: Total organic carbon (TOC) was decreased from an initial 306.3 to 134.1 mg/L, 56.2% TOC removal, after 120 min of treatment for 1:1 H2O2/COD mass ratio and 500/500/1000 mg/L Fe3O4/Fe2O3/Fe0 catalyst doses. The application chromatographic analysis allowed for the detection and identification of pollutants present in the wastewater. Identified pollutants were removed during the treatment processes. Processes carried out at a pH greater than 3.0 were ineffective. The UV process was more effective than the lightless process. Conclusions: The applied processes are effective methods for wastewater treatment. Chromatographic results confirmed the effectiveness of the treatment method. The kinetics of the process were described by the modified second-order model. On the basis of ANOVA results, the hypothesis regarding the accuracy and reproducibility of the research was confirmed. [ABSTRACT FROM AUTHOR]

The direct discharge of industrial wastewater into the environment results in serious contamination. Photocatalytic treatment with the application of sunlight and its enhancement by coupling with electrocatalytic degradation offers an inexpensive and green technology enabling the total removal of refractory pollutants such as surfactants, pharmaceuticals, pesticides, textile dyes, and heavy metals, from industrial wastewater. Among metal oxide—semiconductors, cerium dioxide (CeO2) is one of the photocatalysts most commonly applied in pollutant degradation. CeO2 exhibits promising photocatalytic activity. Nonetheless, the position of conduction bands (CB) and valence bands (VB) in CeO2 limits its application as an efficient photocatalyst utilizing solar energy. Its photocatalytic activity in wastewater treatment can be improved by various modification techniques, including changes in morphology, doping with metal cation dopants and non-metal dopants, coupling with other semiconductors, and combining it with carbon supporting materials. This paper presents a general overview of CeO2 application as a single or composite photocatalyst in the treatment of various pollutants. The photocatalytic characteristics of CeO2 and its composites are described. The main photocatalytic reactions with the participation of CeO2 under UV and VIS irradiation are presented. This review summarizes the existing knowledge, with a particular focus on the main experimental conditions employed in the photocatalytic and photoelectrocatalytic degradation of various pollutants with the application of CeO2 as a single and composite photocatalyst. [ABSTRACT FROM AUTHOR]

The application of Fenton-based advanced oxidation processes (AOPs), such as photo-Fenton or electro-Fenton for wastewater treatment have been extensively studied in recent decades due to its high efficiency for the decomposition of persistent organic pollutants. Usually Fenton-based AOPs are used for the degradation of targeted pollutant or group of pollutants, which often leads to the formation of toxic by-products possessing a potential environmental risk. In this work, we have collected and reviewed recent findings regarding the feasibility of Fenton-based AOPs (photo-Fenton, UVC/H2O2, electro-Fenton and galvanic Fenton) for the detoxification of real municipal and industrial wastewaters. More specifically, operational conditions, relevance and suitability of different bioassays for the toxicity assessment of various wastewater types, cost estimation, all of which compose current challenges for the application of these AOPs for real wastewater detoxification are discussed. [ABSTRACT FROM AUTHOR]

Biocatalysis has developed new molecular tools for the improvement of a wide range of bioprocesses that diminish raw material and energy consumption, while reducing or eliminating the formation of byproducts that might be hazardous to human health and the environment. New advances in the field of biocatalysis apply in the environmental sector, where microorganisms or their enzymes could be used for waste valorization towards the production of high added value products or even the mineralization of xenobiotics. With the aid of enzyme biocatalysis, a series of glucose esters were created with unmodified and modified PHA monomers, showing moderate antimicrobial activity [[5]]. [Extracted from the article]

Industrial sources of environmental pollution generate huge amounts of industrial wastewater containing various recalcitrant organic and inorganic pollutants that are hazardous to the environment. On the other hand, industrial wastewater can be regarded as a prospective source of fresh water, energy, and valuable raw materials. Conventional sewage treatment systems are often not efficient enough for the complete degradation of pollutants and they are characterized by high energy consumption. Moreover, the chemical energy that is stored in the wastewater is wasted. A solution to these problems is an application of photoelectrocatalytic treatment methods, especially when they are coupled with energy generation. The paper presents a general overview of the semiconductor materials applied as photoelectrodes in the treatment of various pollutants. The fundamentals of photoelectrocatalytic reactions and the mechanism of pollutants treatment as well as parameters affecting the treatment process are presented. Examples of different semiconductor photoelectrodes that are applied in treatment processes are described in order to present the strengths and weaknesses of the photoelectrocatalytic treatment of industrial wastewater. This overview is an addition to the existing knowledge with a particular focus on the main experimental conditions employed in the photoelectrocatalytic degradation of various pollutants with the application of semiconductor photoelectrodes. [ABSTRACT FROM AUTHOR]

This paper presents an overview of recent reports on photocatalytic membrane reactors (PMRs) in organic synthesis as well as water and wastewater treatment. A brief introduction to slurry PMRs and the systems equipped with photocatalytic membranes (PMs) is given. The methods of PM production are also presented. Moreover, the process parameters affecting the performance of PMRs are characterized. The applications of PMRs in organic synthesis are discussed, including photocatalytic conversion of CO2, synthesis of KA oil by photocatalytic oxidation, conversion of acetophenone to phenylethanol, synthesis of vanillin and phenol, as well as hydrogen production. Furthermore, the configurations and applications of PMRs for removal of organic contaminants from model solutions, natural water and municipal or industrial wastewater are described. It was concluded that PMRs represent a promising green technology; however, before the application in industry, additional studies are still required. These should be aimed at improvement of process efficiency, mainly by development and application of visible light active photocatalysts and novel membranes resistant to the harsh conditions prevailing in these systems. [ABSTRACT FROM AUTHOR]