Degradation Of Pharmaceuticals In Water Research Articles

Rice husk–based pyrogenic carbonaceous material efficiently promoted peroxymonosulfate activation toward the non-radical pathway for the degradation of pharmaceuticals in water

Pristine pyrogenic carbonaceous material (BRH) obtained from rice husk and modified with FeCl3 (BRH-FeCl3) were prepared and explored as carbocatalysts for the activation of peroxymonosulfate (PMS) to degrade a model pharmaceutical (acetaminophen, ACE) in water. The BRH-FeCl3/PMS system removed the pharmaceutical faster than the BRH/PMS. This is explained because in BRH-FeCl3, compared to BRH, the modification (iron played a role as a structuring agent mainly) increased the average pore diameter and the presence of functional groups such as -COO−, -Si–O−, or oxygen vacancies, which allowed to remove the pollutant through an adsorption process and significant carbocatalytic degradation. BRH-FeCl3 was reusable during four cycles and had a higher efficiency for activating PMS than another inorganic peroxide (peroxydisulfate, PDS). The effects of BRH-FeCl3 and PMS concentrations were evaluated and optimized through an experimental design, maximizing the ACE degradation. In the optimized system, a non-radical pathway (i.e., the action of singlet oxygen, from the interaction of PMS with defects and/or -COO−/-Si–O− moieties on the BRH-FeCl3) was found. The BRH-FeCl3/PMS system generated only one primary degradation product that was more susceptible to biodegradation and less active against living organisms than ACE. Also, the BRH-FeCl3/PMS system induced partial removals of chemical oxygen demand and dissolved organic carbon. Furthermore, the carbocatalytic system eliminated ACE in a wide pH range and in simulated urine, having a low-moderate electric energy consumption, indicating the feasibility of the carbocatalytic process to treat water polluted with pharmaceuticals.

Improvement of the Carbocatalytic Degradation of Pharmaceuticals in Water by the Use of Ultrasound Waves

A carbonaceous material obtained from wood wastes (SW-Mn) was initially used for the removal of pharmaceuticals in water by a carbocatalytic system. The SW-Mn material adsorbed only 41% of the diclofenac (DCF) and 3% of the valsartan (VAL). Interestingly, SW-Mn activated peroxymonosulfate (PMS) and presented a significant increase in the removal rate of DCF, surpassing 90%, while VAL achieved a 24% removal rate at 20 min of treatment. The carbonaceous material was not effective in activating peroxydisulfate or hydrogen peroxide. Nevertheless, the addition of ultrasound waves at 40 kHz to the carbocatalytic system (SW-Mn +PMS) significantly enhanced VAL degradation, exhibiting a high synergy index (4.98). The routes of the degradation were determined using scavengers, and XPS and EPR analyses, evidencing the main action of singlet oxygen in both carbocatalytic and sonocarbocatalytic systems. It is important to note that radicals also participated in the sonocarbocatalytic process, albeit with a minor contribution. The reuse of SW-Mn was tested during various cycles, showing up to a 39.2% VAL degradation rate after the third consecutive reuse. Moreover, the sonocarbocatalytic system was applied to a sample of irrigation crop water spiked with VAL. The treatment induced a partial elimination of the pollutant due to some interfering effects of the matrix components.

Piezo-Photocatalytic Degradation of Pharmaceuticals in Water Using Calcined Natural Sphalerite

This study is the first to report the high performance of calcined natural sphalerite as a heterogeneous catalyst (Catalyst) in the piezo- and photocatalytic degradation of pharmaceuticals (bezafibrate and ceftriaxone) using high-frequency ultrasound (US, 1.7 MHz) and ultraviolet-light-emitting diodes (LED, 365 nm). The kinetic comparison showed that piezo-photocatalysis (LED + US + Catalyst) was more efficient than photocatalysis (LED + Catalyst) for degrading both contaminants in deionized water as well as in surface river water at natural pH (7.9). Despite reducing degradation rates (~1.7 times) in river water due to the scavenging effect of its constituents, ceftriaxone and bezafibrate were degraded by 77% and 48% after 1 h of exposure, respectively. Adding H2O2 increased the corresponding pseudo-first-order rate constants, and the complete degradation of ceftriaxone was achieved. However, the contribution of ultrasound at a given intensity was hidden, which resulted in a similar performance of piezo-photocatalysis and photocatalysis for treating river water. No pronounced synergy between the piezo- and photocatalytic processes was observed in the experimental conditions used. Nevertheless, the H2O2-assisted piezo-photocatalysis using high-frequency US, LED, and natural catalysts can be considered a novel and effective strategy for eliminating pharmaceuticals from real water without pH adjustment.

Theoretical and experimental insight into the construction of FTO/NiSe2/BiVO4 photoanode towards an efficient charge separation for the degradation of pharmaceuticals in water

The increasing contamination of water bodies by pharmaceuticals has become a major environmental concern, with traditional treatment methods often proving ineffective. In this manuscript, we present a theoretical and experimental investigation into the construction of an S-scheme FTO/NiSe2/BiVO4 (NSB) photoanode toward the photoelectrocatalytic degradation of pharmaceutical pollutants in water. The study focuses on the optimization of the photoanode structure to significantly restrain charge recombination and maximize photoelectrocatalytic performance. The photoanode achieves higher efficiency (76%) in comparison with the pristine FTO/BiVO4 (BVO) (43%) and FTO/NiSe2 (NS) (17%) for the PEC degradation of ciprofloxacin. This can be attributed to the improved band gap (1.92 eV), low charge transfer resistance (9.6 Ω), reduced flat band potential (0.24 V) and higher charge density (4.86 × 1017 cm–1) resulting from synergic interaction at the interface of the semiconductor resulting to fast transition of the charge and restraining of recombination of the charge carriers. The accumulation of the electrons majorly takes place at the NS layer as displayed by the theoretical modeling of the charge density difference. This suggests a transition of electrons from BVO to NS. The band offset as well as the built-in electric field across the NSB interface limit the recombination of the photoinduced carriers. The mechanism including the functions of different reactive species is studied, which reveals that the holes mostly dominate the degradation process. Based on density functional theory, active species capture experiment, and photoelectrochemical detection, the synthesized NSB photocatalyst conforms to an S-scheme heterojunction charge transfer mechanism. We consider the composite suitable for the treatment of water contaminated with pharmaceutical waste.

Highly efficient degradation of ofloxacin and diclofenac by composite photocatalyst aloe-emodin/PMMA.

Photocatalysis is one of the most effective methods to remove pollutants from water. Photocatalyst is the core of photocatalysis. The composite photocatalyst combines the photosensitizer with the support and uses the photosensitivity of the photosensitizer and the stability and adsorption of the support to achieve efficient and rapid degradation of pharmaceuticals in water. In this study, natural aloe-emodin with π-conjugated structure was used as photosensitizer to react with macroporous resin polymethylmethacrylate (PMMA) under mild conditions to prepare composite photocatalysts AE/PMMAs. The photocatalyst underwent photogenerated electron migration under visible light to form •O2- and holes with high oxidation activity, which could realize efficient photocatalytic degradation of ofloxacin and diclofenac sodium and showed excellent stability, recyclability and industrial feasibility. This research has developed an efficient method of composite photocatalyst and realized the application of a natural photosensitizer in pharmaceutical degradations.

Photocatalytic Degradation of Diclofenac in Tap Water on TiO2 Nanotubes Assisted with Ozone Generated from Boron-Doped Diamond Electrode

Degradation of pharmaceuticals in water by TiO2 photocatalysis often suffers from low efficiency due to low activity and mass transfer limitation. In this work, diclofenac removal in tap water was performed by photocatalysis on TiO2 nanotube growth on Ti mesh substrate assisted by ozone (O3), which was generated from a hole-arrayed boron-doped diamond (HABDD) film electrode. The vertically oriented TiO2 nanotubes were used as the heterogeneous photocatalyst. The HABDD, as a self-standing diamond electrode, was designed and custom-made by MWCVD technology. The microstructures and crystalline of the TiO2 nanotubes and HABDD were characterized by a scanning electronic micrograph (SEM) and X-ray diffraction (XRD). Unlike other ozone generation methods, direct generation of ozone in the flowing water was applied in the photocatalysis process, and its effect was discussed. The diclofenac removal performance of the electrochemical-photocatalytic system was studied depending on O3 generation efficiency, flowing rate, and the initial diclofenac concentration. The enhanced degradation effect from O3 molecules on TiO2 photocatalysis was attributed to the larger active surface area, the increased photo-generated charge separation rate, and the contact area of O3. The degradation efficiency in the combined electrochemical-photocatalytic TiO2/O3/UV system was higher than that of the O3/UV and TiO2/UV routes individually. Furthermore, a theoretical calculation was used to analyze the TiO2/O3 interface in aqueous media in terms of the final energy. This system created an almost in situ feeding channel of oxidants in the TiO2 photocatalysis process, thus increasing photocatalytic efficiency. This synergetic system is promising in the treatment of pharmaceuticals in water.

Constructing tunable coordinatively unsaturated sites in Fe-based metal-organic framework for effective degradation of pharmaceuticals in water: Performance and mechanism

Micropollutants are ubiquitously detected in the aqueous environment, which needs to be removed by novel materials effectively. Herein, we synthesized a photo-Fenton catalyst based on MIL-53 (Fe) to effectively degrade sulfadimidine, one of the micropollutants in water. Abundant Lewis acid active sites (54.26 μmol/g) were successfully constructed within the metal cluster using FeCl3·6H2O, 1,4-benzene dicarboxylate, and modulators. This study reports a strategy by effectively constructing tunable Lewis acid active sites within the cavities in MIL-53 (Fe) via a facile solvothermal reaction for sixteen micropollutants removal. The photo-Fenton degradation of sulfamethazine was completely removed (∼99%) within only 1 min with a small amount of hydrogen peroxide added. Both theoretical calculation and the experiment results prove that introducing the unsaturated coordinated/lewis acid sites can remarkably reduce the band gap energy and increase the charge-separation efficiency by changing the electron configuration with more distribution asymmetry of structures. The effective degradation of structurally diverse pharmaceuticals with environmentally relevant concentrations was studied by immobilizing MOF-catalyst into a PVDF support. This work advanced the development of effective approaches for emergency contaminants control.

Constructing Tunable Coordinatively Unsaturated Sites in Fe-Based Metal-Organic Framework for Effective Degradation of Pharmaceuticals in Water: Performance and Mechanism

Constructing Tunable Coordinatively Unsaturated Sites in Fe-Based Metal-Organic Framework for Effective Degradation of Pharmaceuticals in Water: Performance and Mechanism

TiO2-carbon microspheres as photocatalysts for effective remediation of pharmaceuticals under simulated solar light

• Carbon microspheres were prepared by hydrothermal carbonization-pyrolysis of lignin. • Carbon microspheres were decorated by TiO 2 by solvothermal treatment. • Photocatalytic removal of pharmaceuticals under simulated solar light was tested. • High conversion and mineralization of diclofenac was achieved. • Diclofenac degradation routes involved C-N cleavage, hydroxylation and cyclization. In this work, novel carbon microspheres supported TiO 2 nanoparticles were prepared for the degradation of pharmaceuticals in water, selecting diclofenac, acetaminophen, and ibuprofen as target pollutants. Lignin, an important biomass byproduct from the paper industry and biorefineries, was transformed in carbon microspheres by a novel approach based on a Fe-activated hydrothermal carbonization followed by pyrolysis at 900 °C. These carbon microspheres were further covered with TiO 2 by a solvothermal treatment. The effects of several parameters including hydrothermal carbonization time and mass ratio (TiO 2 :carbon) on the catalytic activity of TiO 2 -carbon microspheres were investigated. The results revealed that the combination of long carbonization time and high TiO 2 :carbon ratio achieved superior TiO 2 -carbon microspheres (Ti2-C20) catalytic performance. Ti2-C20 achieved complete degradation of ibuprofen (5 mg·L −1 ) and diclofenac (5 mg·L −1 ) within 3 h under solar light and mineralization percentages close to 50%. Moreover, the photocatalytic performance remained high after five reuse cycles and was barely affected by the presence of common inorganic ions in treated wastewater (such as Cl – , NO 3 – and HCO 3 – ). The degradation pathway of diclofenac was proposed, involving C-N bond cleavage, and subsequent hydroxylation and cyclization reactions leading to the formation of aliphatic carboxylic acids. Overall, promising photocatalysts were obtained from a biomass byproduct for effective degradation of pharmaceuticals with the assistance of solar light.

2D materials and its heterostructured photocatalysts: Synthesis, properties, functionalization and applications in environmental remediation

The pharmaceuticals and organic dyes form a large group of contaminants contributing to depleting the water quality and posing a threat to both flora and fauna. These contaminants are generally released from textile and other industrial processes. The recent spread of Covid-19 worldwide has encouraged the infected population to intake antibiotics and antivirals for their recovery as well as a non-infected group to boost their immunity and prevent the spread. As the intake rate increases, the release of eliminated pharmaceuticals into the water bodies increases. Therefore, several techniques have been developed for the efficient degradation of pharmaceuticals in water. In this review, a detailed contribution of different researchers and scientists for the efficient removal of several antibiotics such as chloramphenicol, chlortetracycline, ciprofloxacin, tylosin, etc. is explained. Various routes for both human and veterinary medicines have been explained in detail. An exhaustive collection of bibliographical data has been done with articles in respective domains. Two dimensional (2D) materials and their composites due to their magnificent properties have been in the limelight for ages and have been exploited for potential applications in different areas such as sensing, drug delivery, batteries, and most importantly wastewater treatment. Several techniques with the help of different 2D composites such as photocatalysis, visible light degradation, electrocatalysis, dielectric barrier discharge system, and sonocatalysis have been emphasized to gain knowledge about the current trend and future prospects.

Ferrate(VI)-peracetic acid oxidation process: Rapid degradation of pharmaceuticals in water

This paper presents, for the first time, an oxidation process of ferrate(VI) (Fe(VI), FeO42-)-peracetic acid (CH3C(O)OOH, PAA) to rapidly degrade micropollutants in water. The effect of concentrations of Fe(VI) and PAA showed that complete removal (degradation below detection limit) of a pharmaceutical, carbamazepine (CBZ, 10.0 µM), could be achieved in 60 s at a molar ratio of Fe(VI) to CBZ of 20.0 and 100.0 µM PAA under mild alkaline condition (pH 9.0). The results of the experiments performed in the presence of quenching agents, i.e., tert-butyl alcohol and 2,4-hexadiene, suggested that the iron-based reactive species (Fe(V)/Fe(IV)) and/or acetylperoxyl radicals (CH3C(O)OO●/CH3C(O)O●) were most likely responsible for the rapid oxidation of CBZ, rather than the hydroxyl radical (●OH). The major role of Fe(V)/Fe(IV) was supported by the high mass balance between loss of PMSO and formation of PMSO2 (>90%) during the oxidation of PMSO by Fe(VI)-PAA, which was not observed in the absence of iron species, i.e., PAA-Co(II)-PMSO system having acetylperoxyl radicals as reactive species. Significantly, the Fe(VI)-PAA oxidation process could degrade several other pharmaceuticals (i.e., sulfamethoxazole, sulfadimethoxine, trimethoprim, atenolol, propranolol, and caffeine) within 60 s, indicating its great potential in eliminating pollutants of emerging concern from water.

Cu2O on anodised TiO2 nanotube arrays: A heterojunction photoanode for visible light assisted electrochemical degradation of pharmaceuticals in water

A visible-light active p-n heterojunction photoanode was synthesised via electrodeposition of Cu2O on anodised TiO2 nanotube arrays (NTAs). The photoanode was characterised with XRD, FESEM, EDX and diffusive reflectance UV–Vis, and evaluated by the degradation of ciprofloxacin in water. Mott-Shottky plots were carried out to confirm the formation of the p-n heterojunctions between the two electrodes. Photoelectrochemical properties of the synthesised photoanode were also examined with linear sweep voltammetry, photocurrent response and electrochemical impedance spectroscopy. The linear sweep voltammetry showed that the TiO2 NTA/Cu2O photoanode gave the highest current as compared to the pristine TiO2 NTA. In addition, photocurrent response study showed that the TiO2 NTA/Cu2O gave an improved response three times (0.169 mA cm−2) larger than the pure TiO2 NTA (0.05 mA cm−2). The as-prepared photoanodes were applied in the photoelectrocatalytic degradation of ciprofloxacin an antibiotic. An overall percentage degradation of 73% over a period of 4 h. Trapping experiment revealed that the degradation occurred majorly through the holes on the semiconductor. The photoanodes displayed high stability and reusability and therefore suggests the electrodeposited Cu2O anodised TiO2 NTA electrode as an efficient photoanode for degrading other emerging pharmaceutical pollutants from wastewater.

Degradation of residual pharmaceuticals in water by UV/H<sub>2</sub>O<sub>2</sub> advanced oxidation process

Degradation of residual pharmaceuticals in water by UV/H<sub>2</sub>O<sub>2</sub> advanced oxidation process

The Sonophotocatalytic Degradation of Pharmaceuticals in Water by MnOx-TiO2 Systems with Tuned Band-Gaps

Advanced oxidation processes (AOPs) are technologies to degrade organic pollutants to carbon dioxide and water with an eco-friendly approach to form reactive hydroxyl radicals. Photocatalysis is an AOP whereby TiO2 is the most adopted photocatalyst. However, TiO2 features a wide (3.2 eV) and fast electron-hole recombination. When Mn is embedded in TiO2, it shifts the absorption wavelength towards the visible region of light, making it active for natural light applications. We present a systematic study of how the textural and optical properties of Mn-doped TiO2 vary with ultrasound applied during synthesis. We varied ultrasound power, pulse length, and power density (by changing the amount of solvent). Ultrasound produced mesoporous MnOx-TiO2 powders with a higher surface area (101–158 m2 g−1), pore volume (0-13–0.29 cc g−1), and smaller particle size (4–10 µm) than those obtained with a conventional sol-gel method (48–129 m2 g−1, 0.14–0.21 cc g−1, 181 µm, respectively). Surprisingly, the catalysts obtained with ultrasound had a content of brookite that was at least 28%, while the traditional sol-gel samples only had 7%. The samples synthesized with ultrasound had a wider distribution of the band-gaps, in the 1.6–1.91 eV range, while traditional ones ranged from 1.72 eV to 1.8 eV. We tested activity in the sonophotocatalytic degradation of two model pollutants (amoxicillin and acetaminophen). The catalysts synthesized with ultrasound were up to 50% more active than the traditional samples.

The design of a sunlight-focusing and solar tracking system: A potential application for the degradation of pharmaceuticals in water

Photolysis is considered one of the most important mechanisms for the degradation of pharmaceuticals. Photodecomposition processes to remove pharmaceuticals in water treatment presently use artificial UV light incorporated in advanced oxidation processes. However, UV lighting devices consume a substantial amount of energy and have high operational costs. To develop low energy treatment systems and make good use of abundant sunlight, a natural energy resource as a green technology is needed. As such, a system that combines sunlight focusing, solar tracking and continuous reaction was designed and constructed in the present study, and its application potential as a pharmaceutical water treatment option was tested. Two representative photolabile pharmaceuticals, ciprofloxacin and sulfamethoxazole, were chosen as the target pollutants. The results indicate that the sunlight-focusing system consisting of a UV-enhancing-coated parabolic receiver can concentrate solar energy effectively and hence result in a more than 40% improvement in the direct photolysis efficiency of easily photoconvertible ciprofloxacin. The sunlight-focusing coupled with a solar tracker (SFST) system can improve the sunlight-focusing efficiency by more than 2-fold, thus leading to the maximization of the efficient use of solar energy. Sulfamethoxazole, which is difficult to photoconvert, was successfully degraded by more than 60% compared to direct photolysis through the designed SFST system in the presence of persulfate. The treatment system exhibited good and consistent performance during clear and cloudy days of summer. It is proven that the UV-enhanced coated SFST system with the addition of persulfate indeed has development potential for application in the degradation of pharmaceuticals in water.

Adsorption and catalytic oxidation of pharmaceuticals by nitrogen-doped reduced graphene oxide/Fe3O4 nanocomposite

A novel nanocomposites (N-RGO/Fe3O4) with the function of adsorption and catalytic degradation of pharmaceuticals in water was successfully synthesized through a facile hydrolysis process. The nitrogen modified reduced graphene oxide (N-RGO) incorporated with magnetic Fe3O4 nanoparticles could enhance its adsorption and catalytic activity, and allowed the magnetic separability. The as-prepared N-RGO/Fe3O4 exhibited relatively fast adsorption for norfloxacin (NOR) and ketoprofen (KP), and the maximum adsorption capacity on the N-RGO/Fe3O4 was 158.1 mg/g for NOR and 468.0 mg/g for KP according to the Langmuir fitting. The N-RGO/Fe3O4 composite could activate persulfate (PS) to generate active radicals. NOR degradation kinetics and pathway by N-RGO/Fe3O4/PS system were also investigated. A complete removal of NOR (20 mg/L) was achieved within 210 min with the addition of 10 mmol/L S2O82− and 100 mg/L N-RGO/Fe3O4, and the removal efficiency of total organic carbon (TOC) was 89%. Electron spin resonance (ESR) tests verified that both OH and SO4− were produced in the catalytic oxidation process, and OH played a significant role in the N-RGO/Fe3O4/PS system.

Characterization of BiOX compounds as photocatalysts for the degradation of pharmaceuticals in water

The surface and photophysical properties of bismuth oxyhalide catalysts were determined and correlated with photocatalytic activity. The catalysts themselves were characterized using SEM-EDS, XRD, BET and steady-state luminescence. The photocatalytic potential of these catalysts was determined for their ability to degrade 17 α-ethinyl estradiol (EE2) and estriol at the ppm level in water. The degree of photodecomposition was evaluated using luminescence spectroscopy and HPLC-MS/MS. This is the first time BiOX catalysts have been used to photodegrade synthetic estrogens. Also, this study reports that these BiOX catalysts are more effective at photocatalyzing the selected pharmaceuticals than traditional catalysts such as TiO2. The photocatalytic mechanisms for EE2 and estriol were compared between samples treated with BiOX and TiO2. These BiOX catalysts show great potential as solution to waste water treatment and environmental remediation.

Degradation of Aqueous Pharmaceuticals by Ozonation and Advanced Oxidation Processes: A Review

A vast number of pharmaceuticals have been detected in surface water and drinking water around the world, which indicates their ineffective removal from water and wastewater using conventional treatment technologies. Concerns have been raised over the potential adverse effects of pharmaceuticals on public health and aquatic environment. Among the different treatment options, ozonation and advanced oxidation processes are likely promising for efficient degradation of pharmaceuticals in water and wastewater. Recent progress of advanced oxidation of aqueous pharmaceuticals is reviewed in this paper. The pharmaceuticals and non-therapeutic medical agent of interest include antibiotics, anticonvulsants, antipyretics, beta-blockers, cytostatic drugs, H2 antagonists, estrogenic hormone and contraceptives, blood lipid regulators, and X-ray contrast media.

Heterogeneous photocatalytic degradation of pharmaceuticals in water by using polycrystalline TiO 2 and a nanofiltration membrane reactor

A study of the photodegradation of different pharmaceuticals [furosemide, ranitidine (hydrochloride), ofloxacine, phenazone, naproxen, carbamazepine and clofibric acid] in aqueous medium at various pHs by using a batch photoreactor and a photocatalytic membrane reactor working in recirculation regime was carried out. Polycrystalline TiO 2 was used as the photocatalyst, and different membranes (NTR 7410, PAN GKSS HV3/T, N 30 F, NF PES 10) were tested. A different adsorption of the substrates onto the catalyst surface was observed owing to the hydrophilic/hydrophobic character of the catalyst, depending on the pH. The photodegradation of the seven molecules in the batch reactor was successfully carried out and the behaviour was in accordance with pseudo-first order kinetics. Furosemide and ranitidine were selected to carry out the study of rejection and photodegradation in the hybrid membrane system. The permeate flux of the treated water was in the 31.5–60.0 L/(h m 2) range for NTR 7410 membrane, whereas rejection values in the range 10–60% for furosemide and 5–30% for ranitidine in the dark (without photoreaction) were found. The degradation in the hybrid membrane photoreactor showed that the photocatalyst was retained by the membrane in the reaction ambient, while the membrane rejection towards the pollutants was not very satisfactory. A net decrease of the rejection down to 0 was observed in the contemporary presence of light, photocatalyst and oxygen.