A state of the art review on electrochemical technique for the remediation of pharmaceuticals containing wastewater

A state-of-the-art review on lignocellulosic biomass-derived activated carbon for adsorption and photocatalytic degradation of pollutants: a property and mechanistic study

A promising water treatment method involves using biomass-derived activated carbon (AC) to remove emerging pollutants from wastewater due to its adsorption capacity, cost-effectiveness, and sustainability. Notwithstanding, the existing literature lacks comprehensive studies that specifically focus on removing contaminants in water by comparing the effectiveness of adsorption and photocatalytic degradation methods. Additionally, there is not much emphasis on analyzing the combined processes of adsorption-photocatalytic degradation utilizing AC. Herein, this paper investigates the intricacies of adsorption-photocatalytic degradation mechanisms and contributing variables in the enhancement of performances using biomass-derived AC. Furthermore, this review paper presents a comprehensive examination of different biomass sources employed in the synthesis of AC. It also discusses the diverse techniques utilized for the fabrication of AC, including physical and chemical activation methods. Finally, the shortcomings and future prospects of biomass-derived AC have been addressed. This study offers significant insights for the development of future biomass-derived AC, with the goal of improving their efficiency and expanding their uses in wastewater treatment.

Electrochemical oxidation of a membrane-distillation concentrate for the treatment of real pharmaceutical wastewater

This study presents the first investigation of the electrochemical oxidation of a real membrane-distillation (MD) concentrate for the integrated treatment of highly concentrated pharmaceutical wastewater (PWW). The coupling of electro-Fenton and anodic oxidation applied to a real MD retentate, concentrated by a factor of 1.6 compared to the original PWW, reduced the total organic carbon (TOC) concentration from 23,460 to 12,199 mg/L in 24 h (mineralization efficiency of 48%). The pharmaceutical linezolid (LIN), which appeared in concentrated form in the MD retentate, was completely removed below the detection limit in the process (>99% of LIN degradation within the first 90 min of operation). Despite the high initial toxicity of the retentate, the electrochemical process successfully reduced the toxicity associated with LIN and other organic compounds in the retentate. The energy requirements, normalized to the TOC content, were determined for both the MD (0.056 kWh/gTOC) and the electrochemical (0.016-0.020 kWh/gTOC) processes and proved competitive when compared to alternative treatment options for highly concentrated effluents, such as incineration or supercritical water oxidation. In conclusion, the results showcase the potential of combining MD and electrochemical oxidation for sustainable PWW treatment.

Classification, characteristics, harmless treatment and safety assessment of antibiotic pharmaceutical wastewater (APWW): A comprehensive review

The issues related to the spread of antibiotics and antibiotic resistance genes (ARGs) have garnered significant attention from researchers and governments. The production of antibiotics can lead to the emission of high-concentration pharmaceutical wastewater, which contains antibiotic residues and various other pollutants. This review compiles the classification and characteristics of antibiotic pharmaceutical wastewater (APWW), offers an overview of the development, advantages, and disadvantages of diverse harmless treatment processes, and presents a strategy for selecting appropriate treatment approaches. Biological treatment remains the predominant approach for treating APWW. In addition, several alternative methods can be employed to address the challenges associated with APWW treatment. On the other hand, the present safety assessment of the effluent resulting from APWW treatment is inadequate, necessitating more comprehensive research in this domain. It is recommended that researches in this area consider the issue of toxicity and antibiotic resistance as well. The PNECR model (similar to ecotoxicological PNECs but used to specifically refer to endpoints related to antimicrobial resistance) (Murray et al., 2024) is an emerging tool used for evaluating the antimicrobial resistance (AMR) issue. This model is, characterized by its simplicity and effectiveness, is a promising tool for assessing the safety of treated APWW.

New bacterial strains for ibuprofen biodegradation: Drug removal, transformation, and potential catabolic genes

Ibuprofen (IBU) is a significant contaminant frequently found in wastewater treatment plants due to its widespread use and limited removal during treatment processes. This leads to its discharge into the environment, causing considerable environmental concerns. The use of microorganisms has recently been recognized as a sustainable method for mitigating IBU contamination in wastewater. In this study, new bacteria capable of growing in a solid medium with IBU as the only carbon source and removing IBU from a liquid medium were isolated from environmental samples, including soil, marine, mine, and olive mill wastewater. Four bacterial strains, namely Klebsiella pneumoniae TIBU2.1, Klebsiella variicola LOIBU1.1, Pseudomonas aeruginosa LOIBU1.2, and Mycolicibacterium aubagnense HPB1.1, were identified through 16S rRNA gene sequencing. These strains demonstrated significant IBU removal efficiencies, ranging from 60 to 100% within 14 days, starting from an initial IBU concentration of 5 mg per litre. These bacteria have not been previously reported in the literature as IBU degraders, making this work a valuable contribution to further studies in the field of bioremediation in environments contaminated by IBU. Based on the IBU removal results, the most promising bacteria, K. pneumoniae TIBU2.1 and M. aubagnense HPB1.1, were selected for an in silico analysis to identify genes potentially involved in IBU biodegradation. Interestingly, in the tests with TIBU2.1, a peak of IBU transformation product(s) was detected by high-performance liquid chromatography, while in the tests with HPB1.1, it was not detected. The emerging peak was analysed by liquid chromatography-mass spectrometry, indicating the presence of possible conjugates between intermediates of IBU biodegradation. The proteins encoded on their whole-genome sequences were aligned with proteins involved in an IBU-degrading pathway reported in bacteria with respective catabolic genes. The analysis indicated that strain HPB1.1 possesses genes encoding proteins similar to most enzymes reported associated with the IBU metabolic pathways used as reference bacteria, while strain TIBU2.1 has genes encoding proteins similar to enzymes involved in both the upper and the lower part of that pathway. Notably, in the tests with the strain having more candidate genes encoding IBU-catabolic enzymes, no IBU transformation products were detected, while in the tests with the strain having fewer of these genes, detection occurred.

Comprehensive review of emerging contaminants: Detection technologies, environmental impact, and management strategies

Emerging contaminants (ECs) are a diverse group of unregulated pollutants increasingly present in the environment. These contaminants, including pharmaceuticals, personal care products, endocrine disruptors, and industrial chemicals, can enter the environment through various pathways and persist, accumulating in the food chain and posing risks to ecosystems and human health. This comprehensive review examines the chemical characteristics, sources, and varieties of ECs. It critically evaluates the current understanding of their environmental and health impacts, highlighting recent advancements and challenges in detection and analysis. The review also assesses existing regulations and policies, identifying shortcomings and proposing potential enhancements. ECs pose significant risks to wildlife and ecosystems by disrupting animal hormones, causing genetic alterations that diminish diversity and resilience, and altering soil nutrient dynamics and the physical environment. Furthermore, ECs present increasing risks to human health, including hormonal disruptions, antibiotic resistance, endocrine disruption, neurological effects, carcinogenic effects, and other long-term impacts. To address these critical issues, the review offers recommendations for future research, emphasizing areas requiring further investigation to comprehend the full implications of these contaminants. It also suggests increased funding and support for research, development of advanced detection technologies, establishment of standardized methods, adoption of precautionary regulations, enhanced public awareness and education, cross-sectoral collaboration, and integration of scientific research into policy-making. By implementing these solutions, we can improve our ability to detect, monitor, and manage ECs, reducing environmental and public health risks.

A Comprehensive Review on Modification of Titanium Dioxide-Based Catalysts in Advanced Oxidation Processes for Water Treatment

It has become necessary to develop effective strategies to prevent and reduce water pollution as a result of the increase in dangerous pollutants in water reservoirs. Consequently, there is a need to design new catalyst materials to promote the efficiency of advanced oxidation processes (AOPs) in the field of wastewater treatment plant to ensure the mineralization of trace organic contaminants. A notable approach gaining attention involves the coupling of sulfate radicals-based AOPs to photocatalysis or electrocatalysis processes, aiming to achieve the complete removal of refractory contaminants into water and carbon dioxide. Titanium dioxide as metal oxide has received great attention for its catalytic application in water purification. TiO2 catalysts offer a multitude of advantages in AOPs. They are characterized by their high photocatalytic activity under both ultraviolet and visible light, making them environmentally friendly due to the absence of toxic byproducts during oxidation. Their versatility is remarkable, finding utility in various AOPs, from photocatalysis to photo-Fenton processes. TiO2's durability ensures long-lasting catalytic activity, which is crucial for continuous treatment processes, and their cost-effectiveness is particularly advantageous. Furthermore, their chemical stability allows it to withstand varying pH conditions. However, the large band gap energy and low electrical conductivity hinder the catalytic reaction effectiveness. This review aims to examine various approaches to enhance the catalytic performance of titanium dioxide, with the objective of enabling more efficient water purification methods.

Advances in Biological Wastewater Treatment Processes: Focus on Low-Carbon Energy and Resource Recovery in Biorefinery Context

Advancements in biological wastewater treatment with sustainable and circularity approaches have a wide scope of application. Biological wastewater treatment is widely used to remove/recover organic pollutants and nutrients from a diverse wastewater spectrum. However, conventional biological processes face challenges, such as low efficiency, high energy consumption, and the generation of excess sludge. To overcome these limitations, integrated strategies that combine biological treatment with other physical, chemical, or biological methods have been developed and applied in recent years. This review emphasizes the recent advances in integrated strategies for biological wastewater treatment, focusing on their mechanisms, benefits, challenges, and prospects. The review also discusses the potential applications of integrated strategies for diverse wastewater treatment towards green energy and resource recovery, along with low-carbon fuel production. Biological treatment methods, viz., bioremediation, electro-coagulation, electro-flocculation, electro-Fenton, advanced oxidation, electro-oxidation, bioelectrochemical systems, and photo-remediation, are summarized with respect to non-genetically modified metabolic reactions. Different conducting materials (CMs) play a significant role in mass/charge transfer metabolic processes and aid in enhancing fermentation rates. Carbon, metal, and nano-based CMs hybridization in different processes provide favorable conditions to the fermentative biocatalyst and trigger their activity towards overcoming the limitations of the conventional process. The emerging field of nanotechnology provides novel additional opportunities to surmount the constraints of conventional process for enhanced waste remediation and resource valorization. Holistically, integrated strategies are promising alternatives for improving the efficiency and effectiveness of biological wastewater treatment while also contributing to the circular economy and environmental protection.

FeSO4·7H2O optimisation of earthed atomising corona discharge (Fe-EACD) a process for the pharmaceutical wastewater treatment

Pharmaceutical residues can cause serious water pollution problems, harm human health and destroy the ecological balance. FeSO4·7H2O optimisation of the earthed atomising corona discharge (Fe-EACD) process was used to dispose of pharmaceutical wastewater in this research. Experiments were analyzed by VI characteristic curves to optimise the electrode distance (20-50 mm) and wire electrode diameter (0.3-0.5 mm). The effects of discharging voltage (7-12 kV), time (0-54 min) and FeSO4 dosage (0.2-1.2 g/L) were investigated using the response surface methodology (RSM). According to the RSM results, the best removal efficiency of COD (89.6%) was detected at the optimal discharging voltage of 12 kV, time of 42 min and Fe2+ concentration of 0.4 g/L. The Fe-EACD process could work efficiently with BOD5/COD ratio moving to 0.49 in an acid environment. The kinetic analysis and mechanism study suggested that the Fe-EACD process was demonstrated well by the pseudo-first-order based on the correlation coefficient (R2). Active •OH producing in the EACD process is responsible for the COD removal and the FeSO4·7H2O as a catalyst can promote the formation of active hydroxyl. In other words, EACD with Fe2+ optimisation was an economic and feasible process for pharmaceutical wastewater treatment.

Synergistic effects of layered Ti3C2TX MXene/MIL-101(Cr) heterostructure as a sonocatalyst for efficient degradation of sulfadiazine and acetaminophen in water

In this work, different mass loadings of MXene-coupled MIL-101(Cr) (MXe/MIL-101(Cr)) nanocomposites were generated through a hydrothermal process in order to investigate the potential of this nanocomposite as a novel sonocatalyst for the elimination of sulfadiazine (SD) and acetaminophen (AAP) in aqueous media. The sonocatalytic activity of different MXe/MIL-101(Cr) compositions and surface functionalities was investigated. In addition, the sonocatalytic activities at various pH values, temperatures, pollutant concentrations, catalyst dosages, initial H2O2 concentrations, and organic matter contents were investigated. The experiments on the sonocatalytic elimination of SD and AAP revealed that MXe/MIL-101(Cr) exhibited a catalytic efficiency of ∼ 98% in 80 min when the MXene loading was 30 wt% in the nanocomposite. Under optimized reaction conditions, the degradation efficiency of MXe/MIL-101(Cr) reached 91.5% for SD and 90.6% for AAP in 60 min; these values were 1.2 and 1.8 times greater than those of MXene and MIL-101(Cr), respectively. The high surface area of the MXe/MIL-101(Cr) nanocomposite increased from 4.68 m2/g to 294.21 m2/g, and the band gap of the tagged MIL-101(Cr) on the MXene surface was minimized. The superior sonocatalytic activity of MXe/MIL-101(Cr) was attributed to the effective contact interface, the effective separation rate of e- - h+ pairs through the type II heterostructure interface, and the favorable high free •OH radical production rates that promoted the degradation of SD and AAP. The solid heterointerface between MIL-101(Cr) and MXene was confirmed through Raman and FTIR analysis and was found to promote accessible •OH radical production under sonication, thus maximizing the catalytic activity of nanocomposites. The present results present an effective strategy for the design of a highly efficient, low-cost, reliable sonocatalyst that can eradicate pharmaceutical pollutants in our environment.

CaCu3Ti4O12 Perovskite Materials for Advanced Oxidation Processes for Water Treatment

The many pollutants detected in water represent a global environmental issue. Emerging and persistent organic pollutants are particularly difficult to remove using traditional treatment methods. Electro-oxidation and sulfate-radical-based advanced oxidation processes are innovative removal methods for these contaminants. These approaches rely on the generation of hydroxyl and sulfate radicals during electro-oxidation and sulfate activation, respectively. In addition, hybrid activation, in which these methods are combined, is interesting because of the synergistic effect of hydroxyl and sulfate radicals. Hybrid activation effectiveness in pollutant removal can be influenced by various factors, particularly the materials used for the anode. This review focuses on various organic pollutants. However, it focuses more on pharmaceutical pollutants, particularly paracetamol, as this is the most frequently detected emerging pollutant. It then discusses electro-oxidation, photocatalysis and sulfate radicals, highlighting their unique advantages and their performance for water treatment. It focuses on perovskite oxides as an anode material, with a particular interest in calcium copper titanate (CCTO), due to its unique properties. The review describes different CCTO synthesis techniques, modifications, and applications for water remediation.

Wastewater treatment with algal based membrane bioreactor for the future: Removing emerging containments

The difficulty of developing pollutants in aquatic ecosystems and their potential effects on animals and plants have been raised. Sewage effluent can seriously harm a river's plant and animal life by reducing the water's oxygen content. Due to their increasing use and poor elimination in traditional municipal wastewater treatment plants (WWTPs), pharmaceuticals are one of the developing pollutants that have the potential to penetrate aquatic ecosystems. Due to undigested pharmaceuticals and their metabolites, which constitute a significant class of potentially hazardous aquatic pollutants. Using an algae-based membrane bioreactor (AMBR), the primary objective of this research was to eliminate emerging contaminants (ECs) identified in municipal wastewater. The first part of this research covers the basics of growing algae, an explanation of how they work, and how they remove ECs. Second, it develops the membrane in the wastewater, explains its workings, and uses the membrane to remove ECs. Finally, an algae-based membrane bioreactor for removing ECs is examined. As a result, daily algal production using AMBR technology might range from 50 to 100 mg/Liter. These kinds of machines are capable of nitrogen and phosphorus removal efficiencies of 30-97% and 46-93%, respectively.

Anodic oxidation of sulfamethoxazole paired to cathodic hydrogen peroxide production

A double chamber electrochemical system is developed consisting of a boron-doped diamond (BDD) anode and a graphite cathode, which not only degrades sulfamethoxazole (SMX) but also simultaneously generates hydrogen peroxide (H₂O₂). The degradation of SMX is carried out by (in)direct oxidation at the BDD anode and H₂O₂ is produced by two electron oxygen (O₂) reduction reaction (ORR) at the cathode. The effect of different parameters on the kinetics of both mechanisms was investigated. The performance of the system at the optimized conditions (pH 3, 0.05 M Na₂SO₄ as electrolyte, and 10 mA as applied current) showed that after 180 min of electrolysis, SMX was almost fully degraded (95% removal and ∼90% COD reduction) as well as about 535 μM H₂O₂ was accumulated. With the help of LC-MS, five intermediates formed during SMX electrolysis were properly identified and a degradation pathway was proposed. This study advocates methods for improving the effectiveness of energy use in advanced wastewater treatment.

Treatment of hydrothermal carbonization process water by electrochemical oxidation: Assessment of process performance

Herein electrochemical oxidation (EO) is proposed as a novel path to treat the process water obtained from hydrothermal carbonization of olive tree pruning. The aim of this work is to analyze the organic matter removal achieved by the treatment along with the identification of the chemical species formed after the electro-oxidation process at different experimental conditions. Three different tests were performed in a boron doped diamond cell, using Na₂SO₄ and NaCl as supporting electrolytes to compare the results obtained with the raw process water. The organic matter removal was evaluated by means of total organic carbon and chemical oxygen demand, while Gas Chromatography Mass Spectrometry was used to determine the chemical species present before and after the treatment. The addition of a promoter considerably increased the organic matter removal. In fact, the experiments performed using supporting electrolytes showed the best results in terms of organic matter removal compared to the control experiment (30-40% vs. 17%); This reduction agrees with the volatile fatty acids' measurements. Almost all the chemical species identified in the different feedstocks were partially or totally removed after the EO treatment depending on the experimental conditions. The specific energy consumption and the cost calculated for the treatment is highly dependent on the time of electro-oxidation and the supporting electrolyte used, obtaining values from 1 to 45 €/kg COD_removed. All in all, this work suggests an interesting path towards a further utilization of process water from hydrothermal carbonization processes.

Energy-efficient electrochemical treatment of paracetamol using a PbO2 anode based on pulse electrodeposition strategy: Kinetics, energy consumption and mechanism

The purpose of this research is to study the pulse electrochemical oxidation of paracetamol (PCT) using a novel PbO₂ anode based on pulse electrodeposition strategy (PbO₂-PE). The pulse electrodeposition strategy used to prepare a PbO₂ anode resulted in rougher surface, higher directional specificity of β(101) and more redox couples of Pb⁴⁺/Pb²⁺. Additionally, the oxygen evolution potential (OEP) and charge transfer resistance were also improved. When compared to direct current electrochemical oxidation process, pulse electrolysis in had a slightly higher PCT removal efficiency and active species (·OH and active chlorine) production, while 72.04% of energy consumption was saved. The effects of operating parameters on PCT degradation efficiency and specific energy consumption were studied. The findings suggested that the pulse electrochemical oxidation of PCT followed a pseudo-first-order kinetic model, with PCT removal reaching 98.63% after 60 min of electrolysis under optimal conditions. Possible mechanisms describing reaction pathways for PCT were also proposed. Finally, combinating with the economic feasibility and safety evaluation, we could conclude that pulse electrolysis with a PbO₂-PE electrode was a promising option for improving the practicability of electrochemical treatment for refractory organic wastewater.

Degradation of ciprofloxacin in aqueous solution using ozone microbubbles: spectroscopic, kinetics, and antibacterial analysis

Ciprofloxacin (CIP) has been listed in the last version of the surface water due to its ability to kill human cells by inhibiting the activity of DNA topoisomerase IV. Thus, CIP, along with other antibiotic pollution has become a serious threat to the environment and public health. Ozonation has been used as an advanced technique that is applied in wastewater treatment to remove CIP, but the primary limitation of this method is the low solubility of ozone in water. This study is the first report of CIP removal in a scale-up of its aqueous solution using a self-developed aerator pump-enhanced ozonation (APO) system, which only employs a propeller and a zigzag arrangement of meshes. This aerator pump decreased the size of ozone bubbles by 90% and increased the effective ozone solubility to 0.47 ppm. The mechanism of degradation of CIP is attributed to an oxidation reaction of the antibiotic with reactive oxygen species, such as hydroxyl, oxygen, and hydroperoxyl radicals, generated on the surface of the ozone microbubbles. It was found that the rate and efficiency of degradation of CIP using the APO system were 3.64 × 10⁻³/min and 83.5%, respectively, which is higher compared with those of conventional flow ozonation (FO) systems (1.47 × 10⁻³/min and 60.9%). The higher degradation efficiency of CIP by the APO system was also revealed by its higher electrical energy efficiency (0.146 g/kWh), compared to that of the FO system (0.106 g/kWh). The degradation of CIP was also monitored by the resulting antibacterial activity against Escherichia coli and Staphylococcus aureus.

Current and Future Trends in Environmental Electrochemistry for Wastewater Treatment

In recent years, the demand for high-quality water has constantly been increasing, while at the same time, the legislations regarding wastewater reuse are becoming stricter [...]