Real Wastewater Samples Research Articles

N-doped TiO2 nano particles for photocatalytic degradation of coliform and fecal coliform from hospital wastewater effluent

<p>The photocatalytic process as an advanced oxidation process (AOP) has gained worldwide attention in the water and wastewater industry. The photocatalytic process can be used for water and wastewater disinfection. The aim of this study was to remove coliforms and faecal coliforms from real hospital wastewater using UV and UV/N doped TiO2 photocatalytic process. Secondary wastewater samples were collected from Ali-ebne Abitaleb Hospital, Zahedan. The real wastewater samples containing N-doped TiO2 nanoparticles were exposed to UV light in a reactor. Multi-tube fermentation method (MPN/100ml) was used to count the coliform and faecal coliform bacteria and evaluate the process efficiency. The results showed that the mechanism of inactivation of coliforms and faecal coliforms by N-doped TiO2 nanoparticles and UV light followed the first-order equation, and the simultaneous application of N-doped TiO2 nanoparticles and UV light (N-doped TiO2/UV) increased the efficiency of the photocatalytic process and completely inactivated the coliforms and faecal coliforms in 10 minutes. The results of this study also showed that with increasing contact time, the removal efficiency of coliforms and faecal coliforms increased in the presence of UV light. The highest efficiency of the nanoparticles in bacterial inactivation was achieved at a dose of 120 mg/l in the presence of UV light and was 100%. The nano-photocatalytic process can be used as an efficient method to remove coliforms and faecal coliforms from hospital wastewater, and the N-doped TiO2/UV process is a reliable antibacterial method for water and wastewater disinfection.</p>

Synthesis and application of a novel self‐smart sensor based on a modified amino‐functionalized Zr‐metal–organic framework for rapid and selective detection of some toxic metals in wastewater

In this study, a simple optical luminescence smart sensor derived from organic ligand‐based metal–organic framework material with high oxidation state central metal (Zr4+) was developed. It also was screened to achieve Fe3+, Pb2+, and Co2+ sensitive detection through the strong coordination of amino groups or nitrogen center with 2‐acetylpyridine ligand. The intrinsic optical and fluorescence intensities of sensor were regulated by the ligand‐to‐metal charge transfer effect. The new sensor exhibits an excellent selectivity, ultrafast detection of Fe3+, Pb2+, and Co2+ ions in water with good detection limits (LODs and LOQs). Fluorometric and UV–Vis absorption spectroscopies were used to conduct the study. Brunauer, Emmett, and Teller, Fourier transform infrared (FT‐IR); X‐ray diffraction spectrometry; and X‐ray Photoelectron Spectroscopy were used to confirm the structure of the novel sensor. A real industrial wastewater sample was investigated against the synthesized sensor with a powerful detection efficiency.

A Histogram-Based Technique for Simultaneous Colorimetric Determination of Malachite Green and Brilliant Green Using Triton X-100 Micelle.

Malachite green (MG) and brilliant green (BG) are two synthetic triphenylmethane dyes with applications in the textile and aquaculture industries. They are considered to be environmental contaminants due to their carcinogenic and mutagenic properties. Both dyes have the same bluish-green color in aqueous solutions. The aim of this study is to develop a colorimetric analysis as a very simple and cost-effective method to determine the residues of MG and BG simultaneously in aqueous industrial samples. This method is based on the alterations in red, blue, green (RGB) color histograms of the dyes in the presence and absence of Triton X-100 micelle. The images of the samples were taken by a digital camera and converted to the RGB color system using MATLAB software. Partial least-squares regression as a powerful chemometrics tool was used for multivariate calibrations and quantitative measurements. The performance of the proposed method was compared with a simple spectrophotometric method as a reference. Relative errors of prediction for colorimetric and spectrophotometric analysis, respectively, in micellar media were 6.56 and 4.61% for MG and 6.38 and 5.24% for BG. The shortest linear ranges for colorimetric and spectrophotometric analysis, respectively, in micellar media were 0.1-10 and 0.5-5 mg/L for MG and 0.1-15 and 0.5-6 mg/L for BG. The recovery percentages obtained from the analysis of the dyes in real samples of fish-pond water and textile wastewater ranged between 91 and 107%. The good correlation between the results of the colorimetric analysis and the spectrophotometric analysis indicates the reliability of the proposed colorimetric method. Also, the results of the relative recovery study showed insignificant matrix effect. This study demonstrates the ability of the colorimetric analysis coupled with chemometrics tools for simultaneous determination of the analytes even with nearly identical colors.

Synthesis and Characterization of CeO2/Ag3PO4 p-n Heterojunction Photocatalyst: Its Photocatalytic Activity for the Degradation of Alizarin Yellow Dye

Novel single and binary photocatalysts were synthesized by coprecipitation method. The crystal structure, surface area, morphology, bandgap energy, functional groups, and optical properties were characterized using XRD, BET, SEM-EDX, UV/vis, FTIR, and PL instruments, respectively. Aqueous solutions of the model contaminant alizarin yellow (AY) dye and real wastewater sample solutions were used to evaluate the photocatalytic activity of single and binary nanocomposite. We found that the photocatalytic activity of CeO2/Ag3PO4 binary nanocomposite is higher than that of their individual counterparts. We investigated the effects of operating parameters such as pH, initial dye concentration, and photocatalytic loading on AY dye degradation. Under optimal conditions, the binary system showed an efficiency of 96.99%. The binary photocatalyst showed relatively higher AY photolysis efficiencies than actual wastewater, about 96.56% and 57.76%, respectively. The actions of various scavengers suggest that ·O2 and ·OH scavengers play an important role in AY decomposition. When the reusability of the photocatalyst was tested, only a reduction of about 20% was observed after four consecutive runs. The degradation of AY follows pseudo-first-order kinetics for newly synthesized nanocomposite. This result indicates that the binary nanocomposite can serve as an excellent medium for electron transport.

Photocatalytic Degradation of Psychiatric Pharmaceuticals in Hospital WWTP Secondary Effluents Using g-C3N4 and g-C3N4/MoS2 Catalysts in Laboratory-Scale Pilot

Today, the pollution caused by a multitude of pharmaceuticals used by humans has been recognized as a major environmental problem. The objective of this study was to evaluate and compare the photocatalytic degradation of ten target psychiatric drugs in hospital wastewater effluents using g-C3N4 and 1%MoS2/g-C3N4 (1MSCN) as photocatalytic materials. The experiments were performed using real wastewater samples collected from hospital wastewater treatment plant (WWTP) secondary effluent in spiked and inherent pharmaceutical concentration levels. The photocatalytic experiments were performed in a laboratory-scale pilot plant composed of a stainless-steel lamp reactor (46 L) equipped with ten UVA lamps and quartz filters connected in series with a polypropylene recirculation tank (55–100 L). In addition, experiments were carried out in a solar simulator apparatus Atlas Suntest XLS+ at a 500 Wm−2 irradiation intensity. The analysis of the samples was accomplished by solid-phase extraction, followed by liquid chromatography-Orbitrap high-resolution mass spectrometry. Results showed that the photocatalytic degradation of pharmaceutical compounds followed first-order kinetics. In all cases, 1MSCN presented higher photocatalytic performance than g-C3N4. The removal rates of the pharmaceutical compounds were determined above 30% and 54% using g-C3N4 and 1MSCN, respectively. Parallel to kinetic studies, the transformation products (TPs) generated during the treatment were investigated.

Application of plant-based coagulant with a novel MnO2.MoS2 nanocatalyst in coagulation/photocatalytic ozonation process for wastewater treatment

ABSTRACT In this work, Lallemantia royleana seed mucilage (LRSM) was applied as a plant based coagulant in the initial stage of an integrated method for dye degradation. Photocatalytic ozonation (PCO) process was used under visible-light irradiation in the post-treatment stage. MnO2.MoS2 heterostructure nanocomposite was fabricated by hydrothermal synthesis and applied for the first time in PCO to mineralize Acid Blue 113 dye. The synthesized nanocatalyst was characterized by FT-IR, XRD, FE-SEM, TEM, DRS and BET. Characterization of the nanocatalyst showed that the composite consisted MoS2 with a sheet-like structure and MnO2 in the form of nanoparticles with different sizes in the range of 15–30 nm. By using the response surface methodology (RSM) approach, the best operational condition in the coagulation-flocculation (CF) stage has been acquired at pH 5.0, LRSM dose of 220 mg/L within 27 min. By applying the PCO process, complete decolorization has been attained using 11 mg of the catalyst and 0.2 g/L.h ozone dosage within 9 min. The use of LRSM along with MnO2.MoS2 nanocatalyst in the CF/PCO combined process for treating real wastewater samples indicates that the proposed technique is highly efficient and can be effectively employed to treat dye-containing industrial effluents.

Performance critical comparison of offline SPE, online SPE, and direct injection for the determination of CECs in complex liquid environmental matrices

Sample preparation for the analysis of organic micropollutants in wastewater samples is commonly carried out by solid-phase extraction (SPE) procedures, which involve different manual laboratory operations. This conventional approach requires several hours of counter labour and entail the use of a lot of disposable material, and the subsequent contaminated non-recyclable plastic-residue production. In contrast, by coupling and automatizing the pre-treatment to the instrumental analysis most of that burden erases, sample size gets miniaturized and, thus, storage becomes freed-up. Even lab counters get cleared off from sample pre-treatment apparatus. However, method performance could get alter as a trade-off. This paper presents the results from a study in which methodology, including SPE online-coupled to UHPLC-MS/MS chromatography, was developed for multi-residue (58) determination of veterinary and pharmaceutical drugs in urban and piggery wastewater (influent and effluent to wastewater treatment plants (WWTPs)). Similarly, the direct injection (DI) of large volumes (hundreds of µL) of same matrix samples into the chromatographic system was optimized too. The performance of both automated methods was statistically compared with the classical off-line SPE. As dealing with trace analysis, suitable injection volumes for the alternative approaches were selected on the premise of low limits of quantification (MLQs). Under the selected conditions, validation parameters such as linearity range, method quantification limits, peak shape and carry over were determined. Usually more than 50 % of the analytes showed MLQs below 50 ng/L, for all matrices and methodologies, especially for DI. Real wastewater samples from a local urban WWTP and farm were analysed with all three tested methodologies. Determined concentrations and removal rates were statistically compared and turned out being quite similar. However, analysis under offline SPE and DI approaches provided a larger amount of information as they reached lower MLQs. Offline-SPE provided the worst precision among all.

Uklanjanje boje bemacid red adsorpcijom na piljevini i karbonizovanoj piljevini

Today, huge amounts of coloured wastewater, released into ecosystems are a big problem, because they have harmful effects on humans, the environment, as well as the aquatic environment. One of the common treatments for removing dyes from wastewater is the adsorption process, with an emphasis on the use of cheap adsorbents. Therefore, the subject of this paper is the possibility of removing the anionic dye bemacid red (BR) on wood biomass sawdust and carbonized sawdust. The experiments examined the equilibrium contact time, the effect of initial pH, the effect of adsorbent dose, as well as the effect of the initial adsorbate concentration on the process of adsorption. By applying linear kinetic models, it was found that the adsorption process follows a pseudo-second-order kinetic model. It was found that pH does not have a significant effect on adsorption onto carbonized sawdust. By examining the effect of the initial adsorbent dose, it was found that optimal adsorption requires twice the mass of sawdust compared to carbonized sawdust. The use of linear adsorption isotherms shows better agreement with the Freundlich model for both adsorbents. The maximum adsorption capacity for sawdust is 30.18 mg/kg, while for carbonized sawdust it is 74.60 mg/kg. Use of sawdust and carbonized sawdust can be an effective adsorbent for removing the dye bemacid red from wastewater, which is confirmed by the experiment on a real sample of wastewater. The obtained efficiency of dye removal from real wastewater for sawdust is 42.9 %, and for carbonized sawdust 95.1 %.

Removal of Cu (II) via chitosan-conjugated iodate porous adsorbent: Kinetics, thermodynamics, and exploration of real wastewater sample

Remediation of copper (II) pollutant in aquatic ecosystems is a long-standing concern in the field of water management and the subject of intensive research. In this study, chitosan conjugated iodate porous material (CS-CI) was successfully prepared by media (ammonia, acetic acid, and absolute ethanol) and was used in the treatment of Cu (II) in wastewater samples. Different methods were applied to characterize the CS-CI, including FTIR, SEM, XRD, and TGA. The result showed significant improvement in surface properties and stability when the chitosan was conjugated with the iodate. The adsorption of Cu (II) followed the pseudo-first-order kinetic model and Langmuir isotherm model with a maximum adsorption capacity of 95.2 mg/g. In a complex system (real wastewater), the CS-CI took advantage of the adsorptive properties of both chitosan (CS) and the iodate to significantly improved the remediation of Cu (II) in aqueous media. Therefore, the synthesized chitosan conjugated iodate porous material is promising as an alternative low-cost adsorbent for the treatment of copper (II) in wastewater.

Phenol removal from aqueous environments by natural & chemically modified kaolin clay

AbstractNatural, acid and base modified kaolin clays were studied for the sake of phenol and 4‐chlorophenol removal from aqueous environments and their application to real ground and industrial wastewater samples. Scanning electron microscope (SEM), infrared spectroscopy (IR), X‐ray diffraction (XRD), Thermo Gravimetric Analysis (TGA), Differential Thermal Analysis (DTA), and Surface area analysis were employed for characterization of the adsorbents microstructure. Operating factors such as adsorbent dose, solution pH, initial phenol concentration, and contact time were studied. The experimental data displayed that the increase of the adsorbent dose, contact time, and pH value from 2 to 7 increases the efficiency of the removal process. Optimal conditions for phenolic removal were; contact time of 300 min, primary phenol solution of 25 mg/L, pH 7 and 2.5 g/L as an appropriate adsorbent dose using crude (natural), acid modified and base modified kaolin clays. The higher phenolic removal efficiencies were obtained at 5 mg/L as 90, 97, 96.2%, respectively, for the adsorbents in the previously mentioned order. The adsorption capacity in the removal of phenol and 4‐chlorophenol were 7.481 and 4.195, 8.2942 and 3.211, and 8.05185 and 18.565 mg/g, respectively, for the adsorbents in the same mentioned order. The adsorption equilibrium data were fitted and analyzed with four isotherm models, namely, Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm equations. The adsorption process of phenol on studied adsorbents was exothermic, spontaneous and thermodynamically favorable proved by the negative values of their thermodynamic parameters ΔH° and ΔG°. The correlation coefficient (R2) for all concentrations was higher than 0.94, which indicates that in the studied system, the data suitably fit the first‐order kinetics. The % desorption capacity was amounted to 96%, 91.11%, and 87.06% of adsorbed phenol, respectively, for the adsorbents in the previous order using 0.1N NaOH and 10% V/V ethanol solutions as eluents at 25°C, indicating the reusability of the adsorbents. Kaolin and its modified forms can be introduced as eco‐friendly and low‐cost adsorbents in water remediation implementation.

Closing the loop: Upcycling secondary waste materials into nanoarchitectured carbon composites for the electrochemical degradation of pharmaceuticals

In this study, we demonstrated the application of electrochemical oxidation as a safer and cleaner technology for minimizing the impact of pharmaceuticals in wastewaters, simultaneously mediated by upcycled secondary waste materials (SWMs)-derived electrodes, to further reduce their environmental impact. The modularity, scalability, ease of operation and reliability make electrochemical oxidation an ideal process for the destruction of emerging persistent pollutants; however, their full-scale application is hindered by energy efficiency and the potential release of toxic by-products. Thus, the answer to these issues can be found in the design of tailored multifunctional electrode material. For the first time, SWMs derived from combustion and industrial processes have been employed with the simultaneous dual function of functional fillers, in a polyacrylonitrile fibrous matrix, and as a catalyst for the growth of carbon nanofeatures over the fiber surface, to increase the surface area and charge transfer. Next, the tailored composites were employed as anodes for the electrochemical oxidation of acetaminophen, both in phosphate buffer and in a real wastewater sample. The results suggest that SWMs can substitute costly engineered fillers in carbon-based electrodes and that the absence of reaction by-products (monitored by UHPLC-ESI-MS/MS), together with the low energy consumption, make the tailored fibrous composite electrodes good candidates for the development of safer and cleaner technologies with reduced environmental impact.

Virus inactivation by sequential ultraviolet-chlorine disinfection: Synergistic effect and mechanism

The COVID-19 outbreak has raised concerns about the efficacy of the disinfection process followed in water treatment plants in preventing the spread of viruses. Ultraviolet (UV) and chlorine multi-barrier disinfection processes are commonly used in water treatment plants; however, their effects on virus inactivation are still unclear. In this study, the effects of different disinfection processes (i.e., UV, free chlorine, and their combination) on waterborne viruses were analyzed using bacteriophage surrogates (i.e., MS2 and PR772) as alternative indicators. The results showed that the inactivation rates of PR772 by either UV or free chlorine disinfection were higher than those of MS2. PR772 was approximately 1.5 times more sensitive to UV disinfection and 8.4 times more sensitive to chlorine disinfection than MS2. Sequential UV-chlorine disinfection had a synergistic effect on virus inactivation, which was enhanced by an increase in the UV dose. As compared with single free chlorine disinfection, UV irradiation at 40 mJ cm−2 enhanced MS2 and PR772 inactivation significantly with a 2.7-fold (MS2) and a 1.7-fold (PR772) increase in the inactivation rate constants on subsequent chlorination in phosphate buffered saline. The synergistic effect was also observed in real wastewater samples, in which the MS2 inactivation rate increased 1.4-fold on subsequent chlorination following UV irradiation at 40 mJ cm−2. The mechanism of the synergistic effect of sequential UV-chlorine disinfection was determined via sodium dodecyl sulfate-polyacrylamide gel electrophoresis, using MS2 as an indicator. The results showed that the synergistic effect was due to damage to MS2 surface proteins caused by previous UV disinfection, which enhanced the sensitivity of MS2 to chlorination. This study provides a feasible approach for the efficient inactivation of viruses in water supply and drainage.

Screen-Printed Sensors Coated with Polyaniline/Molecularly Imprinted Polymer Membranes for the Potentiometric Determination of 2,4-Dichlorophenoxyacetic Acid Herbicide in Wastewater and Agricultural Soil

2,4-Dichlorophenoxyacetic acid (2,4-D) is a widely used herbicide worldwide. However, its residues in agricultural products are extremely harmful to human health and to the environment in soil and water. Previous methods for determining 2,4-D in water and soil samples are expensive, cumbersome, and not highly selective. In this study, we developed a novel disposal sensor based on screen-printed electrodes (SPEs) for detecting 2,4-D in wastewater and soil samples. The SPEs were modified with conductive polyaniline (PANI) layer and polyvinyl chloride (PVC) membrane loaded with molecularly printed polymer (MIP). The MIP particles were prepared using 2,4-D as template, methacrylic acid (MAA) as monomer, ethylene glycol dimethacrylate (EGDMA) as cross-linker, and benzoyl peroxide as initiator. The best sensor shows a dynamic concentration range of 10−2 to 10−7 M 2,4-D, a detection limit (LOD) of 3.6 × 10−7 M, Nernst slope (response) of 29.9 mV/decade, and high selectivity over other interfering species previously reported in the literature. The sensors also achieved a short response time of 25 s, high reversibility, and a lifetime of over 2 weeks. The developed sensors were successfully used for determining 2,4-D in real wastewater and soil samples with high accuracy and precision.

Hybrid Polymer Composite of Prussian Red Doped Polythiophene for Adsorptive Wastewater Treatment Application.

Coordination compounds as dopants to conducting polymers combine desirable properties of individual components for a synergistic effect. Prussian red (PR) a low spin iron (III) coordination compound was doped in polythiophene (PTP) matrix to explore propensity of this inorganic-organic hybrid composite material towards wastewater treatment. PR doping was observed to improve mechano, thermal, electrical, and photocatalytic attributes of pure PTP. PTP/PR composite characterization was attempted using the powder X-ray diffraction, TEM, TGA, FTIR, BET analysis and UV-Visible spectroscopy. Optimization of adsorption conditions, adsorbent regeneration, adsorption thermodynamics studies of PTP/PR were carried out using malachite green (MG) dye as a model system. Under optimized conditions 92% MG dye adsorption was observed over 20 mg PTP/PR nanocomposite in 20 minutes at pH 7. PTP/PR nanocomposite also demonstrated a complimentary performance with real wastewater samples. Thermodynamic studies indicate spontaneous process with electrostatic attraction as the predominant noncovalent interaction. This study highlights designing catalysts capable of synergistic adsorption and photocatalytic activities for effective wastewater treatment.

Wood powder biochar in CdS-WPB-g-C3N4 heterojunction as an electron transfer medium for enhancing photocatalytic performance toward degradation methyl orange

Biochar-based photocatalysts were rarely used in wastewater treatment, as the low efficiency of the electron transfer often limited their applicability. In this work, a novel ternary CdS-WPB-CN heterojunction was constructed for the efficient degradation of methyl orange (MO) under UV and visible light. As a green and low-cost electron transfer medium, wood powder biochar (WPB) plays an important role in rapidly transporting photogenerated electrons from g-C3N4 to CdS, significantly improving photogenerated carriers' separation efficiency. Under the optimal degradation condition (1 g/L photocatalyst dosage and 10 mg/L of initial MO concentration), the degradation efficiency for MO of the ternary CdS-WPB(5%)-CN composite reached 99% within 80 min under visible light irradiation. Moreover, it could completely degrade MO within 60 min under UV irradiation. Besides, the outstanding reusability and stability of the CdS-WPB-CN composite were further verified by five consecutive cycle experiments. The degradation experiment in the actual river water body confirmed the excellent applicability in real wastewater samples. Finally, a mechanism was proposed to explain the photocatalytic degradation of MO. Overall, this work provides important insights into the role of biochar in improving the photocatalytic degradation of organic contaminants.

Use of ion chromatographic pulsed amperometric method (IC-PAD) for measuring aqueous sulfide in synthetic and real domestic wastewater

Sulfide detection in domestic wastewater is widely demanded, as sulfide induces odour nuisance and wastewater assets corrosion. However, traditional sulfide detection methods are usually plagued by the limited detection range or interference from impurities. To address these constraints, this study improved the ion chromatographic pulsed amperometric method (IC-PAD) and tested its validity for use in domestic wastewater. Prior to sulfide detection, sulfide-containing sample collection usually requires the use of sulfide antioxidant buffers (SAOB) to minimize sulfide loss. Different sample matrixes require different SAOB recipes, which increases complexity and uncertainty when measuring different environmental samples. Therefore, this study also developed a more convenient and generic sample collection method without the addition of SAOB. The results indicated that the proposed SAOB-free sample collection method could minimize the sulfide loss during sample collection. The IC-PAD method showed a wide linear detection range up to 10 mg-S/L. The detection limit was 3 μg-S/L. Matrix effect studies showed that 1 g/L glucose, formate, acetate, methanol, ethanol, propionate, butyrate, lactate, or sulfate had no evident interference on sulfide measurement. However, 5 mM phosphate buffer led to interference, but reducing the KOH eluent concentration from 62 to 30 mM avoid this interference. Wolfe's vitamin mixture and Wolfe's modified mineral mixture could cause diminutive interference equivalent to 2.53 ± 1.32 μg-S/L sulfide. Moreover, the interference caused by chloride indicated that the IC-PAD method is more applicable for measuring sulfide in low-chloride wastewater. To this end, the IC-PAD method showed high accuracy and precision in the real domestic wastewater samples with chloride concentration of 68 mg/L. The recovery was higher than 97% and the relative standard deviation (RSD) was lower than 1.2%. This study demonstrated the potential use of IC-PAD method for measuring sulfide in real domestic wastewater and possible interference from the solution matrix to be considered.

Toward green nano adsorbents and catalysts: Highly active Fe/Mn nanoparticles for enhanced oxidation of oxytetracycline and levofloxacin

The widespread use of antibiotics, such as oxytetracycline (OTC) and levofloxacin (LEV), has led to dangerous levels of environmental contamination. In this study, functionalized iron/manganese nanoparticles (Fe/Mn NPs), which act as both adsorbent and Fenton catalyst, were green-synthesized using a reducing agent derived from a tea extract. The resulting pre-sorption/Fenton-like oxidation system effectively removed both OTC and LEV from the aqueous solution with adsorption capacities of Fe/Mn NPs for OTC and LEV of 58.8 and 192.3 mg·g−1, respectively. In addition, Fe/Mn NPs also showed high catalytic activity, oxidizing more than 99.9 % of both OTC and LEV, while sodium persulfate (PDS) removed only 26.6 and 29.0 % of OTC and LEV, respectively. Mechanisms of PDS activation typically involve either catalyst-initiated or mediated electron transfer reactions. Fe/Mn NPs through heterogeneous catalytic and metal leaching-induced homogeneous Fenton reactions, which generated various reactive oxygen species (ROS) including 1O2, ·OH, SO4-· and ·O2–. Characterization of Fe/Mn NPs before and after reaction, and the identification of specific OTC and LEV degradation products by LC-MS, helped to elucidate a potential degradation pathway, as well as the removal mechanism. Finally, the practicality of using this system for wastewater treatment was demonstrated using real wastewater samples indicating that the system has great potential for simultaneously degrading both OTC and LEV in contaminated wastewater.

UV and Visible Light Induced Photodegradation of Reactive Red 198 Dye and Textile Factory Wastewater on Fe2O3/Bentonite/TiO2 Nanocomposite

In the present study, the objective was to probe the capacity of the Fe2O3/Bentonite/TiO2 (Fe2O3/B/TiO2) nanoparticles to act as a catalyst in degrading the reactive red 198 (RR198) dye and textile factory wastewater, utilizing irradiation with visible and UV light. The efficiency of this degradation was studied for a variety of experimental parameters by employing real samples of textile wastewater. After 60 min of reaction time, complete degradation of the target pollutant was visible using the synthesized catalyst, i.e., Fe2O3/B/TiO2, under UV light; the same effect was noted after 90 min under visible light. Further, the ease of separation and quick collection of the synthesized Fe2O3/B/TiO2 can result in keeping the photocatalytic efficiency high, as well as raising the reusability. The photocatalytic processes under UV and visible light were found capable of converting the non-biodegradable textile wastewater into biodegradable one. Besides, with the introduction of Daphnia manga, the toxicity of the effluent was examined. Through photocatalysis, utilizing both techniques, the dye toxicity in the solution was fully neutralized, and the intensity of toxicity of the textile effluent was lowered by around 70%. The conclusion drawn in this study showed that the synthesized catalyst displayed good efficiency in removing organic compounds from the textile effluents by both photocatalytic processes using UV and visible light.

Label-free and portable field-effect sensor for monitoring RT-LAMP products to detect SARS-CoV-2 in wastewater

The COVID-19 pandemic caused by the coronavirus SARS-CoV-2 has proven the need for developing reliable and affordable technologies to detect pathogens. Particularly, the detecting the genome in wastewater could be an indicator of the transmission rate to alert on new outbreaks. However, wastewater-based epidemiology remains a technological challenge to develop affordable technologies for sensing pathogens. In this work, we introduce a label-free and portable field-effect transistor (FET)-based sensor to detect N and ORF1ab genes of the SARS-CoV-2 genome. Our sensor integrates the reverse transcription loop-mediated isothermal amplification (RT-LAMP) reaction as a cost-effective molecular detection exhibiting high specificity. The detection relies upon pH changes, due to the RT-LAMP reaction products, which are detected through a simple, but effective, extended-gate FET sensor (EGFET). We evaluate the proposed device by measuring real wastewater samples to detect the presence of SARS-CoV-2 genome, achieving a limit of detection of 0.31 × 10−3 ng/μL for end-point measurement. Moreover, we find the ability of the sensor to perform real-time-like analysis, showing that the RT-LAMP reaction provides a good response after 15 min for concentrations as low as 0.37 ng/μL. Hence, we show that our EGFET sensor offers a powerful tool to detect the presence of the SARS-CoV-2 genome with a naked-eye method, in a straightforward way than the conventional molecular methods for wastewater analysis.

Zeolitic imidazolate frameworks as effective crystalline supports for aspergillus-based laccase immobilization for the biocatalytic degradation of carbamazepine

In this study, zeolitic imidazolate frameworks (ZIF) were employed as effective porous supports for laccase enzyme attachment and further explored synergistic adsorption and biocatalytic degradation of carbamazepine (CBZ) in aqueous solutions. Characterization results from FTIR and NMR analysis confirmed successful incorporation of the laccase enzyme onto ZIF particles. Further analyses from SEM and TEM revealed rhombic dodecahedral morphologies of ZIF crystals with crusts of the enzyme observed on the particles' surface. The carbamazepine degradation results showed that immobilization of the laccase improved its stability and resistance at various pH's, in comparison to the free enzyme. The immobilized laccase also exhibited relatively higher activities across the studied temperature range compared to the free form. Kinetic studies revealed a negligible decline in velocity, Vmax after immobilization, evaluated to be 0.873 and 0.692 mg L−1 h−1 for the free and immobilized laccase, respectively. The immobilized laccase demonstrated improved stabilities towards organic solvents, which qualifies the composite's application in real wastewater samples. In which case, the laccase-ZIF composite proved effective in CBZ decontamination with an efficiency of ∼92%. Furthermore, the immobilized laccase exhibited appreciable storage stabilities (∼70% residual activity) for up to 15 days before any significant loss in activity.