Nanodiamonds decorated yolk-shell ZnFe_(2)O_(4) sphere as magnetically separable and recyclable composite for boosting antibiotic degradation performance

Photocatalysis is an environmentally friendly and energy-saving technology, which can effectively remove persistent dangerous pollutants in the water. Pitifully, optical absorption capacity and carrier separation have become major bottlenecks for marvelous photocatalytic performance of photocatalysts.Herein, to address these issue, Nanodiamonds/yolk-shell ZnFe_(2)O_(4) spheres(NDs/ZFO) nanocomposites were successfully constructed via a facile two-step of solvothermal and calcination methods. The synthesized optimal NDs/ZFO-10 nanocomposite exhibits superior photocatalytic degradation activity of antibiotic under visible light, approximately 85% of the total tetracycline(TC) is degraded, and this photocatalyst shows durable cycling stability. This stems from two aspects of refinement: improvement of light absorption capacity and photo-induced charges migration and separation. In addition, the NDs/ZFO composite photocatalyst features excellent magnetic recovery capability, facilitating the recovery of photocatalyst in industry. This study opens a new chapter in the combination of NDs with magnetic materials, and deepens the understanding of the application of NDs modified composite photocatalysts.

Location and size regulation of manganese oxides within mesoporous silica for enhanced antibiotic degradation

Refractory antibiotics in domestic wastewater are hard to be completely eliminated by conventional methods,and then lead to severe environmental contamination and adverse effects on public health.In present work,advanced oxidation processes(AOPs)are adopted to remove the antibiotic of sul-fachloropyridazine(SCP).Nanosized Mn_(2)O_(3) was fabricated on the SBA-15 material to catalytically acti-vate potassium peroxydisulfate(PDS)to generate reactive oxygen radicals of.OH and SO_(4).for SCP degradation.The effects of location and size of Mn_(2)O_(3) were explored through choosing either the as-made or template free SBA-15 as the precursor of substrate.Great influences from the site and size of Mn_(2)O_(3) on the oxidation activity were discovered.It was found that Mn_(2)O_(3) with a large size at the exterior of SBA-15(Mn-tfSBA)was slightly easier to degrade SCP at a low manganese loading of 1.0-2.0 mmol.g;however,complete SCP removal could only be achieved on the catalyst of Mn_(2)O_(3) with a refined size at the interior of SBA-15(Mn-asSBA).Moreover,the SO_(4).species were revealed to be the decisive radicals in the SCP degradation processes.Exploring the as-made mesoporous silica as a support provides a new idea for the further development of environmentally friendly catalysts.

Single flow treatment degradation of antibiotics in water using falling-film dielectric barrier discharge

The environmental contamination caused by antibiotics is increasingly conspicuous due to their widespread manufacture and misuse. Plasma has been employed in recent years for the remediation of antibiotic pollution in the environment. In this work, a falling-film dielectric barrier discharge was used to degrade the antibiotic tetracycline(TC) in water. The reactor combined the gas-liquid discharge and active gas bubbling to improve the TC degradation performance. The discharge characteristics, chemical species’ concentration, and degradation rates at different parameters were systematically studied. Under the optimized conditions(working gas was pure oxygen, liquid flow rate was 100 mL/min, gas flow rate was 1 L/min,voltage was 20 kV, single treatment), TC was removed beyond 70% in a single flow treatment with an energy efficiency of 145 mg/(kW·h). The reactor design facilitated gas and liquid flow in the plasma area to produce more ozone in bubbles after a single flow under pure oxygen conditions, affording fast TC degradation. Furthermore, long-term stationary experiment indicated that long-lived active species can sustain the degradation of TC. Compared with other plasma treatment systems, this work offers a fast and efficient degradation method, showing significant potential in practical industrial applications.

Bifunctional S-scheme hybrid heterojunction comprising CdS nanorods and BiOIO_(3) nanosheets for efficient solar-induced antibiotic degradation and highly-selective CO_(2) reduction

The development of a bifunctional photocatalyst that can be utilized for both energy conversion and envi-ronmental remediation is of great practical significance.In addition,an S-scheme charge transfer process can assist a photocatalyst in efficiently separating photoexcited electrons and holes while maintaining the strong reducibility and oxidizability of the former and the latter,respectively.We developed a bifunctional S-scheme hybrid photocatalyst comprising CdS nanorods and BiOIO_(3)(BIO) nanosheets for efficient antibi-otic degradation and cocatalyst-and sacrificial reagent-free CO_(2) reduction.The combination of visible-light-responsive one-dimensional(1D)CdS and UV-light-responsive 2D BIO resulted in a CdS/BIO hybrid photocatalyst with effective 1D/2D(line)interfacial contact and a broadened optical absorption range.Notably,the CdS/BIO hybrid exhibited exceptional diclofenac degradation and mineralization as well as outstanding CO_(2) reduction activity for CO production,with 95.4%CO selectivity over H_(2)production.The exceptional performance of the hybrid catalyst is primarily attributed to the accelerated photoexcited charge transfer caused by the 1D/2D line interfacial contact and the high charge separation and strong redox power of the separated charges,both of which stem from the effective S-scheme charge transfer process.In addition,photocorrosion of CdS was substantially mitigated,resulting in the high photocat-alytic performance of the hybrid catalyst even after repeated test runs.This study provides insight into the rational design of bifunctional S-scheme hybrid photocatalysts for CO_(2) reduction and pollutant degra-dation.

A nonradical oxidation process initiated by Ti-peroxo complex showed high specificity toward the degradation of tetracycline antibiotics

Nonradical oxidation has received wide attention in advanced oxidation processes for environmental remediation.Understanding the relationship between material characteristics and their ability to initiate nonradical oxidation processes is the key to better material design and performance.Herein,a novel titanium-based metal-organic framework MIL-125-Ti/H_(2)O_(2) system was established to show a highly selective degradation efficacy toward tetracycline antibiotics.MIL-125-Ti with the abundance of TiO6 octahedra units was found to effectively activate H_(2)O_(2) under dark conditions by forming an oxidative Ti-peroxo complex.The presence of the Ti-peroxo complex,confirmed by UV-visible spectrophotometer,fourier transform infrared spectroscopy,and X-ray photoelectron spectroscopy characterizations,showed superior degradation(>95%removal rate)of oxytetracycline hydrochloride(OTC),doxycycline hydrochloride,chlortetracycline hydrochloride,and tetracycline.Density functional theory calculations were performed to assist the elucidation on the mechanism of H_(2)O_(2) activation and antibiotics degradation.The MIL-125-Ti/H_(2)O_(2) system was highly resistant to halogens and background organics,and could well maintain its original catalytic activity in actual water matrices.It retained the ability to degrade 75%of OTC within ten test cycles.This study provides new insight into the nonradical oxidation process initiated by the unique Ti-peroxo complex of Ti-based MOF.

Degradation of tiamulin by a packed bed dielectric barrier plasma combined with TiO_(2)catalyst

Recently,a plasma catalyst was employed to efflciently degrade antibiotic residues in the environment.In this study,the plasma generated in a packed bed dielectric barrier reactor combined with TiO_(2)catalyst is used to degrade the antibiotic tiamulin(TIA)loaded on the surface of simulated soil particles.The effects of applied voltage,composition of the working gas,gas flow rate and presence or absence of catalyst on the degradation effect were studied.It was found that plasma and catalyst can produce a synergistic effect under optimal conditions(applied voltage 25 k V,oxygen ratio 1%,gas flow rate 0.6 l min^(-1),treatment time 5 min).The degradation efflciency of the plasma combined with catalyst can reach 78.6%,which is 18.4%higher than that of plasma without catalyst.When the applied voltage is 30 k V,the gas flow rate is 1 l min^(-1),the oxygen ratio is 1%and the plasma combined with TiO_(2)catalyst treats the sample for 5 min the degradation efflciency of TIA reached 97%.It can be concluded that a higher applied voltage and longer processing times not only lead to more degradation but also result in a lower energy efflciency.Decreasing the oxygen ratio and gas flow rate could improve the degradation efflciency.The relative distribution and identity of the major TIA degradation product generated was determined by high-performance liquid chromatography–mass spectrometry analysis.The mechanism of TIA removal by plasma and TiO_(2)catalyst was analyzed,and the possible degradation path is discussed.

Screening of an Effective Degrading Strain for Treatment of Antibiotic Pharmaceutical Wastewater and Determination of Its Biological Properties

In this study,an effective antibiotic-degrading strain NG3 was isolated from activated sludge of antibiotic wastewater treatment.According to the results of morphological,physiological and biochemical identification and phylogenetical analysis of 16S r DNA sequence,the isolated strain belonged to Acinetobacter sp.,which was named Acinetobacter sp.NG3.Moreover,biological properties of the isolated strain were analyzed preliminarily,which provided a basis for the application of Acinetobacter sp.NG3 strain in efficient treatment of antibiotic industrial wastewater.

Ta_(3)N_(5)/CdS Core–Shell S‑scheme Heterojunction Nanofibers for Efficient Photocatalytic Removal of Antibiotic Tetracycline and Cr(VI):Performance and Mechanism Insights

Ta_(3)N_(5)/CdS core–shell S-scheme heterojunction nanofibers are fabricated by in situ growing CdS nanodots on Ta_(3)N_(5) nanofib-ers via a simple wet-chemical method.These Ta_(3)N_(5)/CdS nanofibers not only affords superior photocatalytic tetracycline degradation and mineralization performance,but also cause an efficient photocatalytic Cr(VI)reduction performance.The creation of favorable core–shell fiber-shaped S-scheme hetero-structure with tightly contacted interface and the maximum interface contact area promises the effective photo-carrier disintegration and the optimal photo-redox capacity synchronously,thus leading to the preeminent photo-redox ability.Some critical environmental factors on the photo-behavior of Ta_(3)N_(5)/CdS are also evaluated in view of the complexity of the authentic aquatic environment.The degradation products of tetracycline were confirmed by HPLC–MS analyses.Furthermore,the effective decline in eco-toxicity of TC intermediates is confirmed by QSAR calculation.This work provides cutting-edge guidelines for the design of high-performance Ta_(3)N_(5)-based S-scheme heterojunction nanofibers for environment restoration.

A data-based review on norfloxacin degradation by persulfate-based advanced oxidation processes:Systematic evaluation and mechanisms

Persulfate-based advanced oxidation processes(AOPs)have obtained increasing attention due to the generation of sulfate radical(SO_(4)-)with high reactivity for organic contaminants degradation,Numerous activation methods have been used to activate two common persulfates:peroxymonosulfate(PMS)and peroxydisulfate(PDS).However,the comparisons of activation methods and two oxidants in the comprehensive degradation performance of the target contaminant are still limited.Thus,taking norfloxacin(NOR)as the target contaminant,we proposed five key parameters(the observed pseudo-first-order rate constant,kobs;average mineralization rate,rm;utilization efficiency of catalyst,Ucat;utilization efficiency of oxidant,Uox;and net utilization efficiency of oxidant,Uox')to quantify the comprehensive degradation performance of NOR.The irradiation affected target pollutants,catalysts,and oxidants,leading to an improved degradation performance of NOR.Various heterogeneous catalysts were compared in terms of the key elements contained.Fe,Co,and Mn-based materials performed better,while carbon-based catalysts performed poorly on NOR degradation.The overall degradation performance of NOR was different for PMS and PDS,which can be ascribed to their varied reaction pathways towards NOR,but stemmed from different properties of PMS and PDS.Besides,the effect of pH on the degradation efficiency of NOR was investigated.A neutral solution was optimal for PMS system,while an acidic solution worked better for PDS system.Finally,we analyzed the molecule structure of NOR by density functional theory(DFT)calculation to study the sites easy to attack.Then,we summarized four typical degradation pathways of NOR in SO_(4)^(-)-based AOP systems,including defluorination,piperazine ring cleavage,piperazine ring oxidation,and quinoline group transformation.

Recent advances in H_(2)O_(2)-based advanced oxidation processes for removal of antibiotics from wastewater

As important emerging contaminants, antibiotics have caused potential hazards to the ecological environment and human health due to their extensive production and consumption. Among various techniques for removing antibiotics from wastewater, H_(2)O_(2)-based advanced oxidation processes(AOPs) have received increasing attention due to their fast reaction rate and strong oxidation capability. Hence this review critically discusses:(i) Recent research progress of AOPs with the addition of H_(2)O_(2) for antibiotics removal through different methods of H_(2)O_(2) activation;(ii) recent advances in AOPs that can in-situ generate and activate H_(2)O_(2) for antibiotics removal;(iii) H_(2)O_(2)-based AOPs as a combination with other techniques for the degradation and mineralization of antibiotics in wastewater. Future perspectives about H_(2)O_(2)-based AOPs are also presented to grasp the future research trend in the area.

Full-spectrum Bi@SrTiO_(3) for bi-directional promotion effects on photocatalytic redox reaction:Insight into intermediates and mechanism

The development of full-spectrum photocatalysts active in the near-infrared(NIR)region has gained increasing attention for deleterious pollutant removal.The integration of plasmonic metals with semico nductors is an effective way to widen the light re sponse range of photocatalysts due to the strong light absorption and fast plasmonic energy transfer of the localized surface plasmon resonance(LSPR).In this work,the full-spectrum responsive Bi@SrTiO_(3) was prepared via facile solvothermal chemical reduction.The optimal Bi@SrTiO_(3) achieves exceptional photocatalytic Cr(VI)reduction efficiency and tetracycline degradation,realizing bi-directional promotion effects on redox reaction.According to density functional theory(DFT)simulations,the extraordinary photocatalytic performance is attributed to the tunable builtin electric field(IEF)of the Ohmic contact.The favorable adaptability in real water and high stability of BSTO-25 were proved by experime ntal results.And the po ssible photocatalytic mechanism was proposed based on theoretical calculation and experimental results.Furthermore,the non-toxicity of the BSTO-25 was evaluated by E.coli cultivation,which further proves the feasibility of treating wastewater with BSTO-25.This work provides a new perspective on constructing full-spectrum-driven photocatalysts for applications dealing with environmental remediation.

Rationally designed Ta_(3)N_(5)/BiOCl S-scheme heterojunction with oxygen vacancies for elimination of tetracycline antibiotic and Cr(Ⅵ):Performance,toxicity evaluation and mechanism insight

S-scheme heterojunction photocatalysts have been the“stars”in the field of photocatalysis.Herein,a novel S-scheme heterojunction of Ta_(3)N_(5)/BiOCl with oxygen vacancies(OVs)was fabricated via a facile method.The charge separation and transport mechanism of this Ta_(3)N_(5)/BiOCl S-scheme heterojunction was verified by the analyses of band energy structures,active species,photoelectric behaviors and DFT theoretical calculation.Compared with Ta_(3)N_(5)and BiOCl,the Ta_(3)N_(5)/BiOCl unveils substantially upgraded photocatalytic property under visible light,and the photocatalytic efficiency for removal of tetracycline(TC)and hexavalent chromium(Cr(VI))reaches 89.6%and 91.6%,respectively.The substantial enhancement of the photocatalytic activity is attributed to the synergistic effect of the S-scheme hetero-structure and oxygen vacancies,which improves the visible-light absorption,while promoting the spatial separation of charge carriers with the optimum redox capacity,thereby boosting the production of active species for catalytic reactions.The TC degradation pathway is deduced and the toxicity evolution of TC is appraised using the QSAR method.In a nutshell,this work gives a deep understanding of the photocatalytic mechanism based on Ta_(3)N_(5)/BiOCl as well as presents a newfangled thought for developing highly efficient S-scheme heterojunction photocatalysts for water decontamination.

Catalytic degradation of lomefloxacin by photo-assisted persulfate activation on natural hematite:Performance and mechanism

The natural hematite(α-Fe_(2)O_(3)) is stable and abundant on the earth,as well as with strange electronic band structure and good visible light absorption properties.However,the composition and catalytic performance of natural hematite should be explored.In this study,the photo-assisted hematite nanoparticles activated persulfate(H-NPs/PS/vis)system was constructed.As detected,H-NPs had an irregular agglomerate structure with abundant internal pore and were mainly composed of Fe_(2)O_(3),SiO_(2) and TiO_(2).The system was applied to removing various antibiotic(i.e.,lomefloxacin,ciprofloxacin and enrofloxacin with initial concentration of 10 mg/L),achieving high degradation performance of 82.0%,81.2%and 82.2%after120,330 and 240 min,respectively.Moreover,H-NPs had excellent reusability with low metal leaching(Ti leaching percentage lower than 0.01%,Fe dissolution percentage was 0.48%)and stable structure.At last,a possible reaction mechanism of H-NPs/PS/vis system was proposed that lomefloxacin(LOM)was efficiently removed via the synergistic process of components contained in H-NPs with PS and light,involving the generation of·O_(2)^(-),·OH and SO_(4)^(·-).Above all,this paper provided a novel application scheme of natural hematite through in-depth and comprehensive experimental exploration.

Photocatalytic degradation of sulfadiazine in suspensions of TiO_(2)nanosheets with exposed(001)facets

Antibiotics such as sulfonamides are widely used in agriculture as growth promoters and medicine in treatment of infectious diseases.However,the release of these antibiotics has caused serious environmental problems.In this paper,photocatalytic oxidation technology was used to degrade sulfadiazine(SDZ),one of the typical sulfonamides antibiotics,in UV illuminated TiO_(2)suspensions.It was found that TiO_(2)nanosheets(TiO_(2)-NSs)with exposed(001)facets exhibit much higher photoreactivity towards SDZ degradation compared to TiO_(2)nanoparticles(TiO_(2)-NPs)with a rate constant increases from0.017 min^(-1)to 0.035 min^(-1),improving by a factor of 2.1.Under the attacking of reactive oxygen species(ROSs)such as superoxide radicals(*O_(2)^(-))and hydroxyl radicals(*OH),SDZ was steady degraded on the surface of TiO_(2)-NSs.Based on the identification of the produced intermediates by LC–MS/MS,possible degradation pathways of SDZ,which include desulfonation,oxidation and cleavage,were put forwards.After UV irradiation for 4 h,nearly 90%of the total organic carbon(TOC)can be removed in suspensions of TiO_(2)-NSs,indicating the mineralization of SDZ.TiO_(2)-NSs also exhibits excellent stability in photocatalytic degradation of SDZ in wide range of pH.Even after recycling used for 7 times,more than 91.3%of the SDZ can be efficiently removed,indicating that they are promising to be practically used in treatment of wastewater containing antibiotics.

Reinventing MoS2 Co-catalytic Fenton reaction:Oxygen-incorporation mediating surface superoxide radical generation

To better understand the mechanisms of hydrogen peroxide(H_(2)O_(2))’s decomposition and reactive oxygen species(ROS)’s formation on the catalyst’s surface is always a critical issue for the environmental application of Fenton/Fenton-like reaction.We here report a new approach to activate H_(2)O_(2) in a co-catalytic Fenton system with oxygen incorporated MoS2,namely MoS_(2−x) O_(x) nanosheets.The MoS_(2−x) O_(x) nanosheets assisted co-catalytic Fenton system exhibited superior degradation activity of emerging antibiotic contaminants(e.g.,sulfamethoxazole).Combining density functional theory(DFT)calculation and experimental investigation,we demonstrated that oxygen incorporation could improve the intrinsic conductivity of MoS_(2−x) O_(x) nanosheets and accelerate surface/interfacial charge transfer,which further leads to the efficacious activation of H_(2)O_(2).Moreover,by tuning the oxygen proportion in MoS_(2−x) O_(x) nanosheets,we are able to modulate the generation of ROS and further direct the oriented-conversion of H_(2)O_(2) to surface-bounded superoxide radical(·O_(2−surface)).It sheds light on the generation and transformation of ROS in the engineered system(e.g.,Fenton,Fenton-like reaction)for efficient degradation of persistent pollutants.