Removal of emerging pollutants in water treatment plants: adsorption of methyl and propylparaben onto powdered activated carbon

Plants, animals, and fisheries waste-mediated bioremediation of contaminants of environmental and emerging concern (CEECs)-a circular bioresource utilization approach

The release of contaminants of environmental concern including heavy metals and metalloids, and contaminants of emerging concern including organic micropollutants from processing industries, pharmaceuticals, personal care, and anthropogenic sources, is a growing threat worldwide. Mitigating inorganic and organic contaminants, which can be coined as contaminants of environmental and emerging concern (CEECs), is a big challenge as traditional physicochemical processes are not economically viable for managing mixed contaminants of low concentrations. As a result, low-cost materials must be designed to provide high CEEC removal efficiency. One of the environmentally viable and energy-efficient approaches is biosorption, which involves using biomass or biopolymers isolated from plants or animals to decontaminate heavy metals in contaminated environments using inherent biological mechanisms. Among chemical constituents in plant biomass, cellulose, lignin, hemicellulose, proteins, polysaccharides, phenolic compounds, and animal biomass include polysaccharides and other compounds to bind heavy metals covalently and non-covalently. These functional groups include carboxyl, hydroxyl, carbonyl, amide, amine, and sulfhydryl. Cation-exchange capacities of these bioadsorbents can be improved by applying chemical modifications. The relevance of chemical constituents and bioactives in biosorbents derived from agricultural production such as food and fodder crops, bioenergy and cash crops, fruit and vegetable crops, medicinal and aromatic plants, plantation trees, aquatic and terrestrial weeds, and animal production such as dairy, goatery, poultry, duckery, and fisheries is highlighted in this comprehensive review for sequestering and bioremediation of CEECs, including as many as ten different heavy metals and metalloids co-contaminated with other organic micropollutants in circular bioresource utilization and one-health concepts.

Carbon-based single-atom catalysts in advanced oxidation reactions for water remediation: From materials to reaction pathways

Single-atom catalysts (SACs) have been widely recognized as state-of-the-art catalysts in environment remediation because of their exceptional performance, 100% metal atomic utilization, almost no secondary pollution, and robust structures. Most recently, the activation of persulfate with carbon-based SACs in advanced oxidation processes (AOPs) raises tremendous interest in the degradation of emerging contaminants in wastewater, owning to its efficient and versatile reactive oxidant species (ROS) generation. However, the comprehensive and critical review unraveling the underlying relationship between structures of carbon-based SACs and the corresponding generated ROS is still rare. Herein, we systematically summarize the fundamental understandings and intrinsic mechanisms between single metal atom active sites and produced ROS during AOPs. The types of emerging contaminants are firstly elaborated, presenting the prior pollutants that need to be degraded. Then, the preparation and characterization methods of carbon-based SACs are overviewed. The underlying material structure-ROS type relationship in persulfate-based AOPs is discussed in depth to expound the catalytic mechanisms. Finally, we briefly conclude the current development of carbon-based SACs in AOPs and propose the prospects for rational design and synthesis of carbon-based SACs with on-demand catalytic performances in AOPs in future research.

Synthesis of biochar-CoFe2O4 nanocomposite for adsorption of methylparaben from wastewater under full factorial experimental design

The presence of endocrine-disrupting chemicals in municipal wastewater has emerged as a threat to human health and the environment. Therefore, this study aimed to develop biochar-cobalt ferrite (BCF) nanocomposite for the removal of methylparaben from water under the full factorial experimental design of 4 factors with 3 levels (3⁴). The biochar-CoFe₂O₄ nanocomposite was developed by co-precipitation method from cobalt ferrite and biochar of Eucalyptus tree bark. Adsorbent surface morphology and functional and elemental composition were carried out by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and energy-dispersive X-ray spectroscopy (EDS) techniques which showed the presence of cracks with a rough surface, reasonable surface chemical composition, and many chemical functional groups, respectively. The experimental and predicted adsorption efficiencies ranged from 25.3 to 85.6% and 21.8 to 80.3%, respectively. The maximum adsorption performance (85.6%) reduced the methylparaben concentration from 27.5 to 4.0 mg/L at the optimum condition of adsorbent dose of 55 mg/100 mL, pH 6, contact time 90 min, and the initial methylparaben concentration of 27.5 mg/L. However, the adsorbent dose was the most influential main factor whereas the least influential was the interaction between solution pH and contact time under the regression model. The model also showed that 69% methylparaben removal was described by the regression model. The experimental data best fitted with the Freundlich model indicate multilayer adsorption which is the implication of physisorption. The sorption mechanism is attributed to Vander Waals forces, H-bonding, and dipole interaction. This BCF nanocomposite adsorbent appears to be promising for the removal of methylparaben from wastewater, but a further optimization process is essential to boost the treatment performance.

Biochar Obtained from Caryocar brasiliense Endocarp for Removal of Dyes from the Aqueous Medium

Given the increase in environmental pollution, especially of water, the emergence of studies that seek to develop strategies to mitigate/treat such effects have gained prominence in the world scientific community. Among the numerous adsorption processes, those made from biochar production stand out. This study analyzed the adsorption properties of the blue methylene model dye in the aqueous solution of biochar and activated biochar developed from pequi (Caryocar brasiliense) endocarp. The biochar was characterized, before and after adsorption, by infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffractometry (XRD), and thermogravimetric analysis (TG). The surface load of the materials was performed by the point of zero charge (pH_PZC) method. The study also included analyses of contact time parameters and adsorbed concentration in the adsorption process. Morphological analysis showed that a more significant and profound number of fissures and pores appeared in the activated biochar compared to the biochar. Residual mass analysis evidenced that biochar lost about 15% more mass than the activated biochar, indicating that activation occurred satisfactorily. The adsorption process was well adjusted by pseudo-second-order kinetics and Langmuir's isothermal model. The activated biochar achieved an excellent adsorption capacity of 476.19 mg.g^-1, thus demonstrating to be a sound system for removing dyes from an aqueous medium.

Endocrine disrupting chemicals (EDCs) in environmental matrices: Occurrence, fate, health impact, physio-chemical and bioremediation technology

Endocrine disrupting chemicals (EDCs) are an emerging category of toxicity that adversely impacts humans and the environment's well-being. Diseases like cancer, cardiovascular risk, behavioral disorders, autoimmune defects, and reproductive diseases are related to these endocrine disruptors. Because these chemicals exist in known sources such as pharmaceuticals and plasticizers, as well as non-point sources such as agricultural runoff and storm water infiltration, the interactive effects of EDCs are gaining attention. However, the efficiency of conventional treatment methods is not sufficient to fully remediate EDCs from aqueous environments as the occurrence of EDC bioremediation and biodegradation is detected in remediated drinking water. Incorporating modification into current remediation techniques has to overcome challenges such as high energy consumption and health risks resulting from conventional treatment. Hence, the use of advanced psychochemical and biological treatments such as carbon-based adsorption, membrane technology, nanostructured photocatalysts, microbial and enzyme technologies is crucial. Intensifying environmental and health concerns about these mixed contaminants are primarily due to the lack of laws about acute concentration limits of these EDCs in municipal wastewater, groundwater, surface water, and drinking water. This review article offers evidence of fragmentary available data for the source, fate, toxicity, ecological and human health impact, remediation techniques, and mechanisms during EDC removal, and supports the need for further data to address the risks associated with the presence of EDCs in the environment. The reviews also provide comprehensive data for biodegradation of EDCs by using microbes such as fungi, bacteria, yeast, filamentous fungi, and their extracellular enzymes.

Emerging contaminants of high concern for the environment: Current trends and future research

Wastewater is contaminated water that must be treated before it may be transferred into other rivers and lakes in order to prevent further groundwater pollution. Over the last decade, research has been conducted on a wide variety of contaminants, but the emerging contaminants are those caused primarily by micropollutants, endocrine disruptors (EDs), pesticides, pharmaceuticals, hormones, and toxins, as well as industrially-related synthetic dyes and dye-containing hazardous pollutants. Most emerging pollutants did not have established guidelines, but even at low concentrations they could have harmful effects on humans and aquatic organisms. In order to combat the above ecological threats, huge efforts have been done with a view to boosting the effectiveness of remediation procedures or developing new techniques for the detection, quantification and efficiency of the samples. The increase of interest in biotechnology and environmental engineering gives an opportunity for the development of more innovative ways to water treatment remediation. The purpose of this article is to provide an overview of emerging sources of contaminants, detection technologies, and treatment strategies. The goal of this review is to evaluate adsorption as a method for treating emerging pollutants, as well as sophisticated and cost-effective approaches for treating emerging contaminants.

Pharmaceutical compounds used in the COVID-19 pandemic: A review of their presence in water and treatment techniques for their elimination

During the COVID-19 pandemic, high consumption of antivirals, antibiotics, antiparasitics, antiprotozoals, and glucocorticoids used in the treatment of this virus has been reported. Conventional treatment systems fail to efficiently remove these contaminants from water, becoming an emerging concern from the environmental field. Therefore, the objective of the present work is to address the current state of the literature on the presence and removal processes of these drugs from water bodies. It was found that the concentration of most of the drugs used in the treatment of COVID-19 increased during the pandemic in water bodies. Before the pandemic, Azithromycin concentrations in surface waters were reported to be in the order of 4.3 ng L^-1, and during the pandemic, they increased up to 935 ng L^-1. Laboratory scale studies conclude that adsorption and advanced oxidation processes (AOPs) can be effective in the removal of these drugs. Up to more than 80% removal of Azithromycin, Chloroquine, Ivermectin, and Dexamethasone in aqueous solutions have been reported using these processes. Pilot-scale tests achieved 100% removal of Azithromycin from hospital wastewater by adsorption with powdered activated carbon. At full scale, treatment plants supplemented with ozonation and artificial wetlands removed all Favipiravir and Azithromycin, respectively. It should be noted that hybrid technologies can improve removal rates, process kinetics, and treatment cost. Consequently, the development of new materials that can act synergistically in technically and economically sustainable treatments is required.

Typical groundwater contamination in the vicinity of industrial brownfields and basic methods of their treatment

The article deals with simple methods of decontamination of groundwater from the vicinity of brownfields contaminated with organic and inorganic substances. In the literature, thousands of articles on this issue at various sophisticated levels of knowledge can be found. The articles are mostly suitable as an extension of scientific knowledge; however, regarding potential costs and respectively scale-up problems, the applications are limited. It turns out that the vast majority of contaminated water can be effectively decontaminated by simple methods, in a coagulation-sedimentation sequence → simple oxidation and reduction methods for separated water (Fenton reaction, photocatalysis, ozonation, reductive dehalogenation with zero metals) → adsorption of remaining pollutants on simple sorbents, eg on biochar → (possibly bioremediation or advanced physical methods such as membrane filtration) → final purification on activated carbon. Due to the usually limited volume loads of soils with pollutants in the vicinity of brownfields, it is not economically advantageous to build demanding decontamination units for water purification. Usually, the simplest solution is the system to pump-and-treat around the source of contamination, with the main emphasis on highly effective removal of pollutants from water that returns underground. Groundwater was taken from boreholes leading to the saturated zone in the vicinity of several selected industrial brownfields. The solutions are shown on individual typical cases.

Simultaneous adsorptive removal of conventional and emerging contaminants in multi-component systems for wastewater remediation: A critical review

The rapid growth of population and industrialization results in pollution of freshwater sources which leads to the water stress conditions on the world in future. Adsorption is a low cost and popular technique for the removal of contaminants from water bodies. Most of the reports till date are on removal of a single component from aqueous solutions using this technique, but the real-world effluent contains multiple contaminants such as dyes, heavy metals, pesticides, antibiotics and many more. Therefore, a study on simultaneous removal of contaminants is highly needed to obtain a suitable adsorbent that can be used commercially. This critical review provides a detailed study on the removal of contaminants in the presence of other contaminant/s i.e., from a multi-component system (MCS). The different possible interaction mechanisms in MCS like synergism, antagonism and non-interaction are discussed. The MCS containing the mixture of conventional contaminants such as heavy metals and dyes, and other emerging contaminants such as antibiotics, organic contaminants, pesticides and personal care products are explained in depth. This review article will be helpful for researchers working in the field of simultaneous removal of contaminants from MCSs for wastewater remediation.

Insights into Paraben Adsorption by Metal-Organic Frameworks for Analytical Applications

Metal-organic frameworks (MOFs) are attractive materials used as sorbents in analytical microextraction applications for contaminants of emerging concern (CECs) from environmental liquid matrices. The demanding specs for a sorbent in the analytical application can be comprehensively studied by considering the interactions of the target analytes with the frameworks by the use of single-crystal X-ray diffraction, computational analysis, and adsorption studies, including the kinetic ones. The current study intends a better understanding of the interactions of target CECs (particularly, propylparaben (PPB) as a model) and three Zn-based layered pillared MOFs: CIM-81 [Zn₂(tz)₂(bdc)] (Htz = 1,2,4-triazole and H₂bdc = 1,4-benzenedicarboxylic acid) and their amino derivatives [Zn₂(NH₂-tz)₂(bdc)] CIM-82 and [Zn₂(tz)₂(NH₂-bdc)] CIM-83 (NH₂-Htz = 3-amino-1,2,4-triazole and NH₂-H₂bdc = 2-amino-1,4-benzenedicarboxylic acid). The crystal structures of the two solvate compounds (dma@CIM-81 (dma = dimethylacetamide) and acetone@CIM-81) were solved by single-crystal X-ray diffraction to determine the points of interaction between the framework and the guest molecules. They also served as a starting point for the computational modeling of the PPB@CIM-81 compound, showing that up to two PPB molecules can be hosted in one of the pores, while only one can be trapped in the second pore type, leading to a maximum theoretical capacity of 291.9 mg g^-1. This value is close to the value obtained by the adsorption isotherm experiment for CIM-81 (283 mg g^-1). This value is, by far, higher than those previously reported for other materials for the removal of PPB from water, and also higher than the experimental values obtained for CIM-82 (54 mg g^-1) and CIM-83 (153 mg g^-1). The kinetics of adsorption is not very fast, with uptake of about 40% in 3 h, although a 70% release in methanol is achieved in 1 h. In addition, a further comparison of performance in analytical microextraction (requiring only 10 mg of CIM-81) was carried out together with chromatographic analysis to support all insights attained, with the method being able to monitor CECs as low as μg L^-1 levels in complex environmental water samples, thus performing successfully for water monitoring even in multicomponent scenarios.

Carbamazepine and Diclofenac Removal Double Treatment: Oxidation and Adsorption

In the present research, the effect of two hybrid treatments, ozone followed by powdered activated carbon (PAC) or PAC followed by ozone (O₃), was studied for the removal of two drugs present in water: diclofenac and carbamazepine. In the study, two initial concentrations of each of the contaminants, 0.7 mg L^-1 and 1.8 mg L^-1, were used. Different doses of PAC between 4-20 mg L^-1 were studied as variables, as well as different doses of O₃ between 0.056-0.280 mg L^-1. The evolution of the concentration of each contaminant over time was evaluated. From the results obtained, it was concluded that the combined treatment with ozone followed by PAC reduces between 50% and 75% the time required to achieve 90% removal of diclofenac when compared with the time required when only activated carbon was used. In the case of carbamazepine, the time required was 97% less. For carbamazepine, to achieve reduction percentages of up to 90%, O₃ treatment followed by PAC acted faster than PAC followed by O₃. In the case of diclofenac, PAC treatment followed by O₃ was faster to reach concentrations of up to 90%. However, to reach yields below 80%, O₃ treatment followed by PAC was more efficient.

Application of adsorption process for effective removal of emerging contaminants from water and wastewater

Emerging pollutants in the marine ecosystem, as well as their possible impact on live species, have become a rising cause of worry. A traditional wastewater treatment plants alone are not successful in eliminating such massive contaminant groups and therefore additional water treatment is required which is to be cost effective. Since standard primary and secondary treatment plants are unsuccessful at eliminating or degrading these harmful chemicals, a cost-effective tertiary treatment approach is proposed. Adsorption is a successful approach for Contaminants removal globally, because it is low installation expense, high performance and has easy operational design. Emerging pollutants have been removed from wastewaters using various adsorbents like activated carbons, improved bio chars, Nano adsorbents, hybrid adsorbents, and others. The purpose of this paper is to review the source of contaminants and the concept of adsorption when separating emerging contaminants. The present study aims to examine the adsorption mechanism as an effective approach for treating emerging contaminants. Then, the analysis of natural and man-made adsorbents for the separation of contaminants is examined along with its comparison. Also, future view on emerging contaminants and adsorbents in modern generation has been discussed.

A review on effective removal of emerging contaminants from aquatic systems: Current trends and scope for further research

Wastewater is water that has already been contaminated by domestic, industrial and commercial activity that needs to be treated before it could be discharged into some other water bodies to avoid even more groundwater contamination supplies. It consists of various contaminants like heavy metals, organic pollutants, inorganic pollutants and Emerging contaminants. Research has been doing on all types of contaminates more than a decade, but this emerging contaminants is the contaminants which arises mostly from pharmaceuticals, personal care products, hormones and fertilizer industries. The majority of emerging contaminants did not have standardized guidelines, but may have adverse effects on human and marine organisms, even at smaller concentrations. Typically, extremely low doses of emerging contaminants are found in the marine environment and cause a potential risk to the aquatic animals living there. When contaminants emerge in the marine world, they are potentially toxic and pose many risks to the health of both man and livestock. The aim of this article is to review the Emerging contaminate sources, detection methods and treatment methods. The purpose of this study is to consider the adsorption as a beneficial treatment of emerging contaminants also advanced and cost effective emerging contaminates treatment methods.

Magnetic Photocatalyst for Wastewater Tertiary Treatment at Pilot Plant Scale: Disinfection and Enrofloxacin Abatement

In this work, we have tested a photocatalytic material consisting of a core of SiO2/Fe3O4 coated with TiO2 (Magnox) for plausible tertiary wastewater treatment. For this, a pilot plant of 45 L equipped with an Ultraviolet light (UVC) lamp was employed to study the degradation of a model contaminant, enrofloxacin (ENR), as well as water disinfection (elimination of Escherichia coli and Clostridium perfringens). The influence of different operational conditions was explored by means of dye (rhodamine-B) decolorization rates, analyzing the effects of photocatalyst quantity, pH and recirculation flow rates. The magnox/UVC process was also compared with other four Advanced Oxidation Processes (AOPs): (i) UVC irradiation alone, (ii) hydrogen peroxide with UVC (H2O2/UVC), (iii) Fenton, and (iv) photo-Fenton. Although UVC irradiation was efficient enough to produce total water disinfection, only when employing the AOPs, significant degradations of ENR were observed, with photo-Fenton being the most efficient process (total enrofloxacin removal in 5 min and c.a. 80% mineralization in 120 min, at pH0 2.8). However, Magnox/UVC has shown great pollutant abatement effectiveness under neutral conditions, with the additional advantage of no acid or H2O2 addition, as well as its plausible reuse and simple separation due to its magnetic properties.

Assessing the applicability of a new carob waste-derived powdered activated carbon to control pharmaceutical compounds in wastewater treatment

This paper assesses the applicability of a new carob waste-derived powdered activated carbon (PAC) obtained by steam activation for pharmaceutical compounds (PhCs) removal in urban wastewater treatment plants (WWTPs) with activated sludge (AS) secondary treatment. The new carob-derived PAC presents chemical and textural properties similar to a high-performing commercial PAC produced from vegetable source by physical activation. The adsorption isotherms of three target PhCs, carbamazepine, diclofenac and sulfamethoxazole, spiked (at around 100 μg/L) in mixed liquor (ML) and in clarified-ML from the AS-bioreactor of a WWTP show: (i) minor reduction of PAC capacity with real MLs compared to clarified MLs; (ii) the higher the PhC hydrophobicity, the higher the PAC adsorption capacity in both water matrices; (iii) hydrophobic interactions probably overweight electrostatic interactions between the PhCs and the slightly positively charged PAC in these real water matrices with background organics and inorganics. The PhC adsorption results with ML and clarified-ML are used to calibrate the IAST-based tracer model (TRM) and predict the new PAC performance when added to AS-bioreactor vs. in post-secondary treatment, at the PhC naturally-occurring trace concentrations. The modelling projections show (i) one needs higher PAC doses than those reported in the literature, particularly in post-treatment, and (ii) the benefits of PAC dosing to the bioreactor, with only a slightly higher PAC dose being needed when compared to its post-secondary dosing and minimising the capital investment.

Activated Carbon and Ozone to Reduce Simazine in Water

In this study, the reduction of the pesticide simazine at an initial concentration of 0.7 mg L−1 in water has been investigated using two different technologies: adsorption with powdered and granulated activated carbon, advanced oxidation processes with ozone and finally, the combination of both technologies. The results obtained for a carbon dose of 16 mg L−1 show that powdered activated carbon, with contact times of 60 min, obtained 81% of reduction and in 24 h 92%, while granulated activated carbon at 60 min obtained a reduction of 2%, rising to 34% after 24 h of contact time. Therefore, powdered activated carbon achieves better reductions compared to granulated; when ozone was applied at a dose of 19.7 mg L−1, with a reaction time of 18 min, a reduction of 93% was obtained, achieving a better reduction in less time than with adsorption treatments; however, during oxidation, by-products of simazine were produced. In the combined treatments, with the same doses of carbon and ozone mentioned above, the treatment that starts with ozone followed by activated carbon powder is recommended due to the adsorption in the last phase reaching a 90% reduction of the simazine and its by-products in 38 min of time.

Enhanced removal of the endocrine disruptor compound Bisphenol A by adsorption onto green-carbon materials. Effect of real effluents on the adsorption process

The high exposure to the endocrine disrupting compounds (EDC) in water represents a relevant issue for the health of living beings. The xenoestrogen Bisphenol A (BPA), a suspected EDC, is an industrial additive broadly used for manufacturing polycarbonate and epoxy resins. Due to its harmful effect in humans and the aquatic environment, an efficient method to remove BPA from wastewater is urgently required. The present work aims to study the adsorption of BPA from aqueous solutions onto carbonaceous materials, e.g., a synthesized carbon xerogel (RFX), a chemical-activated carbon from Kraft lignin (KLP) and a commercial activated carbon (F400) for comparative purposes. Batch kinetic and adsorption tests of BPA in ultrapure water were accomplished, finding higher adsorption capacities of BPA onto both F400 activated carbon (q_sat = 407 mg g^-1) and the biochar KLP (q_sat = 220 mg g^-1), versus to that obtained for the xerogel (q_sat = 78 mg g^-1). Furthermore, kinetic experiments revealed faster kinetic adsorption for RFX and KLP materials, achieving the equilibrium time within 24 h, attributed to their more-opened porous structure. Pseudo-first order, pseudo-second order, Elovich, intra-particle diffusion and film diffusion models were used to fit the experimental data. Thus, the BPA adsorption isotherms were analysed by Langmuir, Freundlich, Sips, Redlich-Peterson and Dual-site Langmuir (DLS) isotherm models.In addition, the influence of different aqueous matrices, such as a hospital wastewater, a wastewater treatment plant (WWTP) effluent and a river water, on BPA removal efficiency has been explored. These adsorption tests revealed a clear competitive effect between the target compound (BPA) and the natural organic matter content (NOM) present in the matrices for the active sites, resulting in a high decreasing of BPA adsorption removal.