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[Display omitted] • ZrO 2 -CaCr 2 O 4 -BiOIO 3 nanocomposite were synthesised by facile co-precipitation method. • The NCs exhibits excellent photodegradation of cefixime and doxycycline. • The end product toxicity was evaluated against E.coli and S.epidermis. • Investigation of genotoxicity towards Allium cepa. • Elucidation of photodegradation pathway using ECOSAR software. Today, diverse form of antibiotic drugs has been used extensively for the treatment of various microbe related diseases. The improper handling and overusage of these antibiotics have tremendously affected the aquatic system. Therefore, the development of low cost and highly efficient photocatalyst for the effective degradation of antibiotics is paramount for the remediation of toxic pollutants in water bodies. In the present study, the ternary ZrO 2 -CaCr 2 O 4 -BiOIO 3 nanocomposite (NC) has been newly fabricated under simple chemical co-precipitation technique. The developed ternary NC was investigated for the photodegradation of cefixime (CFX) and doxycycline (DOX) under visible light irradiation. The prepared NC was characterized by various physiochemical analysis including HR-TEM, SEM, UV–vis DRS, XPS, FT-IR, ESR, PL, Raman, EIS, and N 2 adsorption and desorption analysis. The reusability of the photocatalyst was tested by performing six consecutive cycles. The toxicity of the degraded end products of CFX and DOX has been evaluated against E. coli and S. epidermis. The fabricated NC was investigated for its photodegradation efficiency under different parameters such as pH, antibiotic concentration, and NC dosage. The photodegradation mechanism was elucidated using scavenging study, and ESR analysis. The TOC results confirmed the complete mineralisation of CFX and DOX. Also, the possible degradation pathway of CFX and DOX was determined based on GC–MS analysis. The fabricated NC were investigated for the genotoxicity towards Allium cepa. The present study opens up a new insight for using ZrO 2 -CaCr 2 O 4 -BiOIO 3 photocatalyst for remediation of pharmaceutical pollutant. [ABSTRACT FROM AUTHOR]

In this work, ZnFe 2 O 4 was coupled with ZnO nanorods for the development of ZnO/ZnFe 2 O 4 heterojunction. The particles were synthesized via a simple co-precipitation assisted solvothermal method. The existence of elements, morphology, structure and the nature of the prepared nanomaterials were characterized using several characterization techniques such as SEM, TEM, EDAX, XPS, FTIR, XRD, Raman, UV–vis DRS, PL, EIS and ESR. The catalyst containing 60% doped ZnFe 2 O 4 showed the best performance amongst others (20% and 40%) and the controls. ZnO/ZnFe 2 O 4 -60 showed 94% degradation efficiency against tetracycline in 240 min under visible light with a rate constant of 0.011 min−1. The mechanism of degradation was explained using the results obtained from the scavenging experiments. The TOC analysis confirmed the complete mineralization of the TC by the NCs. The intermediate compound formed was identified and the degradation pathway was elucidated by GC-MS analysis and the plausible pathway was further confirmed according to the values obtained from the Fukui function. The reusability and stability studies reveal the high photo-stable nature of the prepared NCs. Thus, this current work can be considered as a potential candidate for effective the removal of toxic pollutants from wastewater. [Display omitted] • ZnFe 2 O 4 decorated on ZnO nanorods was prepared via co-precipitation assisted solvothermal method. • Superior photocatalytic degradation of TC was exhibited by ZnO/ZnFe 2 O 4 -60%. • Hydroxyl radical are the major species involved in the photodegradation process. • Excellent reusability and structural stability were shown by the NC. • The NCs possessed anti-fungal activity. [ABSTRACT FROM AUTHOR]

• MoO 3 @N or S-Fe 3 O 4 nanohybrid fabricated via facile hydrothermal method. • Nanohybrid exhibited superior photodegradation of CFX (98%) and Cr(VI) reduction (99.7%). • Nanohybrid showed good photostability and reusability. • The nanohybrid could separate by external magnetic field after usage. • Genotoxicity of nanohybrid was investigated on A. cepa. Herein, a multifunctional magnetic N or S doped Fe 3 O 4 loaded MoO 3 nanorods (NRs) were constructed by facile hydrothermal method. The developed nanohybrid showed superior photocatalytic degradation of cefixime (CFX) (98.0%) and photocatalytic reduction of Cr(VI) (99.7%) in presence of visible light illumination. The constructed nanohybrid was fully characterized by HR-TEM, Raman, FE-SEM, VSM, FT-IR, XPS, ESR, EIS, PL, UV–vis DRS and N 2 adsorption and desorption analysis to understand its physiochemical characteristics. The nanohybrid showed excellent reusability within six consecutive cycles, and easily separable due to its good magnetic property. The optimization studies were done to understand the efficiency of the photocatalyst under various conditions including pH, temperature and nanohybrid dosages. The toxicity of the photodegraded products was evaluated towards gram negative (E. coli) and gram positive (S. aureus) bacteria. Furthermore, a possible photodegradation pathway was investigated based on GC–MS/MS analysis to better understand the photodegradation process. Also, the fabricated nanohybrid was investigated for its genotoxicity towards Allium cepa. The present research opens a new insight for magnetic MoO 3 @S-Fe 3 O 4 -50% as a photocatalyst for environmental remediation. [ABSTRACT FROM AUTHOR]

Water pollution is becoming an inevitable problem in today's world. Tons and tons of wastewater with hazardous pollutants are getting discharged into the clean water bodies every day. In this regard, photocatalytic environmental remediation using nanotechnology such as the use of organic, metal and non-metal based semiconductor photocatalysts for photodegradation of pollutants has gained enormous attention in the past few decades. This review is focused particularly on graphitic carbon nitride (g-C 3 N 4) which is a cheap, metal-free, polymeric photoactive compound and it is used as a potential photocatalyst in wastewater treatment. Though, pristine g-C 3 N 4 is a good photocatalyst, it has certain drawbacks such as poor visible light absorption capacity, quicker recombination of photoelectrons and holes, delayed mass and charge transfer, etc. As a result, the pristine g-C 3 N 4 catalyst is modified into novel 0D, 1D, 2D and 3D morphologies such as nano-quantum dots, nanorods, nanotubes, nanowires, nanosheets, nanoflakes, nanospheres, nanoshells, etc. It was also tailored into novel composites along with various compounds through doping, metal deposition, heterojunction formation, etc., to enhance the photocatalytic property of pure g-C 3 N 4. The modified catalysts showed promising photocatalytic performance such as degradation of majority of pollutants in the environment. It also showed excellent results in the removal or reduction of heavy metals. This review provides a detailed record of g-C 3 N 4 and its diverse photocatalytic applications in the past years and it provides knowledge for the development of such similar novel compounds in the future. [Display omitted] • The study highlights the g-C 3 N 4 based photocatalysts in wastewater treatment. • Synthesis of g-C 3 N 4 using different methods to obtain various morphologies. • Tailoring g-C 3 N 4 through doping, metal deposition, heterojunction formation. • Mechanism for wastewater treatment and H 2 production using photocatalytic process. • An outlook for exploration of novel g–C 3 N 4 –based nanomaterials in further studies. [ABSTRACT FROM AUTHOR]

[Display omitted] • Photocatalytic nano-materials reviewed for the degradation of ibuprofen. • Remediation performance and mechanism are qualitatively and quantitatively described. • Interfacial regulation strategies of catalysts to improve degradation of ibuprofen. • Toxic effects of ibuprofen, end products of degradation on aquatic organisms, human beings, etc., were discussed. The usage of personal care products, pharmaceutically active compounds, dyes, and pesticides causes a great impact on aquatic organisms as well as human beings. Elimination of such persistent and eco-toxic pharmaceutically active compounds present in the sewage is a vital thrust area in environmental management. The designing and fabrication of efficient photocatalyst for degrading such compounds is one of the challenging and interesting aspects of photocatalysis. In this review, interfacial regulation strategies of photocatalysts, degradation pathways, and eco-toxicological effects of ibuprofen along with its intermediates have been discussed. Interfacial regulation strategies of catalysts can improve their performances in the degradation of ibuprofen by photocatalysis. The construction of nano-heterojunction and selection of co-catalyst is one of the most important parts for improving the catalyst performance. The photocatalytic efficiency of nano-heterojunctions is higher owing to its low rate of electron-hole (e−/h+) recombination, cost efficiency and improved light utilization. The role of co-catalyst in charge separation and electric conductivity has been discussed. The degradation efficiency of different photocatalysts has been collectively discussed. The toxic effects of ibuprofen on aquatic organisms, human beings, etc., have been discussed briefly. The photocatalytic degradation pathway of ibuprofen based on the active radical and the intermediate compounds along with their toxicity have been compared to other pharmaceuticals in this review. The future scopes in photocatalysis technology and its practical applications have been discussed. [ABSTRACT FROM AUTHOR]

Phenolic compounds are widely used in various industrial processes, but they can be harmful to the environment if released without proper treatment. In this study, we developed a ternary nanocomposite (NCs) consisting of molybdenum trioxide, bismuth oxoiodide, and chromium-doped cadmium sulphide quantum dots h-MoO 3 /Bi 9 O 7 I 3 /Cr–CdS QDs (MBC) nanocomposite (NCs) to enhance the photocatalytic degradation of p-chlorophenol (p-CP). The nanomaterial morphology, distribution of depositing material, and heterojunction formation were investigated using SEM, TEM, SAED, and elemental mapping. Further, the structural characterization was done by XRD, XPS, and Raman spectroscopy which confirmed its purity, chemical states, bonding nature, and the presence of oxygen vacancies (OVs) and sulphur defects. The 30-MBC NCs exhibited the highest surface area of 354.5 m2/g and pore volume of 0.76 cm3/g, with the H3 hysteresis loop indicating their mesoporous nature. The Kubelka-Munk plot determined the band gap of the NCs to be 2.22 eV and ensured successful visible-light sensitization. PL and ESR studies revealed that 30-MBC NCs had the lowest charge carrier recombination and highest ROS production. The photocatalytic degradation of p-CP by 30-MBC NCs achieved 94% in 300 min. The highest efficiency was observed at 75 mg/L NCs, 150 mg/L p-CP, and pH 6. Additionally, NCs retained activity in the presence of different ions and degraded 82% p-CP even after six consecutive cycles. •O 2 − was the dominant ROS involved in the degradation process, while OVs and sulphur defects played a crucial role in ameliorating charge transfer in the 30-MBC NCs. GC-MS/MS analysis identified the possible degradation pathways of p-CP, and ECOSAR showed that less toxic by/end products were produced. Overall, this study highlights the promising potential of 30-MBC NCs for extensive wastewater treatment. [Display omitted] • Ternary h-MoO 3 /Bi 9 O 7 I 3 /Cr–CdS NCs (30-MBC NCs) were successfully constructed. • Various characterization studies confirmed their superior photocatalytic properties. • 30-MBC NCs achieved 94% degradation of p-chlorophenol in 300 min under visible light. • The degradation mechanism followed a dual S-scheme. • The degradation pathway of p-CP was projected, and the end products were found to be less toxic. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fe-doped Pr 6 O 11 -MoO 3 @g-C 3 N 4 n - n heterojunction was constructed. • Doping of Fe caused metal-oxidation state cycling and interstitial defect states, thereby enhanced the photo-Fenton process. • Doxycycline photodegradation and photoinactivation of S. epidermis reached 98% and 95% respectively. • Mechanism of photocatalysis and degradation pathway were elucidated. • OH was found to be the primary ROS involved in photocatalysis. Photocatalysis is a clean technology that can be applied to water treatment processes. In this study, we have constructed n - n heterojunction between Fe-doped Pr 6 O 11 -MoO 3 and g-C 3 N 4 with a flower-on-sheet morphology (Fe/Pr 6 O 11 -MoO 3 @g-C 3 N 4 NCs). The fabricated nanomaterials were characterized using XRD, XPS, SEM, TEM, SAED, EDX, elemental mapping, PL, DRS, BET, EIS and ESR. The photogenerated charge carriers were produced through three routes - internal electric field caused by n - n heterojunction, dynamic cycling of Fe3+/Fe4+ and Pr3+/Pr4+ metal-oxidation states due to photo-Fenton processes, and the interstitial defect states caused by Fe doping. Interestingly, 30-FPMG NCs attained 98% doxycycline degradation in 280 min and 95% S. epidermis bacterial photoinactivation at 50 mg/L dosage. Here, OH was the primary ROS involved in the photocatalytic process. The effects of NPs dosage, drug concentration, pH and ions were tested. The stability was examined for six consecutive cycles. The photodegradation intermediates were predicted using GC–MS and ECOSAR software was used to assess their toxicity. [ABSTRACT FROM AUTHOR]

The development of an efficient and robust photocatalyst is of great importance for the effective treatment of toxic pollutants. In this study, novel Ag 3 PO 4 microspheres were decorated on the nanorod embedded flower-like BiOBr designed for the effective photodegradation of methyl orange (MO) and malachite green (MG) dyes. The synthesized particle was characterized to understand the structural and morphological features using HR-TEM, XRD, SEM, PL, ESR, FT-IR, XPS, EIS and N 2 adsorption and desorption. The degradation rate constants for MG (0.0132 min−1) were 3.47 and 3.14 times greater than BiOBr and Ag 3 PO 4. Similarly, the rate constants for MO degradation (0.0151 min−1) are 3.87 and 3.97 times greater than BiOBr and Ag 3 PO 4. The effect of initial MG and MO dye concentration, reaction pH, nanocomposite (NC) concentration was investigated. The NC exhibited excellent visible light photodegradation of 99.8% for MO and 93.4% for MG dyes at 180 min and 200 min respectively. A S-scheme heterojunction were proposed as the possible mechanism for the photodegradation of the dyes. The prepared photocatalyst exhibits excellent structural stability and reusability. The toxicity of the intermediates were predicted by the ecotoxicity analysis using ECOSAR software where the end products were less toxic than parent MG and MO. The degradation pathway were elucidated to predict the possible intermediates and to confirm the complete mineralization of the compound using GC-MS analysis. The proposed study can be implemented for practical application for the degradation of organic pollutants present in the water bodies. • Ag 3 PO 4 microspheres were decorated on the flower-like BiOBr. • BiOBr/30%Ag 3 PO 4 exhibited superior photodegradation of MO and MG dyes. • BiOBr/Ag 3 PO 4 shown excellent stability and recyclable properties. • Heterojunction of semiconductor accelerated separation of photoelectron-hole pairs. [ABSTRACT FROM AUTHOR]

The synthesis of CeO 2 /MnFe 2 O 4 NCs has been carried out by ultrasonication-assisted co-precipitation method. Transmission electron microscopic (TEM) analysis confirmed the embedment of MnFe 2 O 4 over CeO 2 with clear lattice fringes. Energy dispersive analysis (EDAX) and elemental mapping confirm the existence of elements including Ce, Mn, Fe, and O. The XRD patterns of the NCs indicated the effective construction of crystalline CeO 2 /MnFe 2 O 4 NCs with the co-existence of CeO 2 and MnFe 2 O 4 in desired molar ratio. The degradation rate constant of CeO 2 /MnFe 2 O 4 NCs-1:1 under visible light illumination was estimated to be 0.0108 min−1, which was 2.2 and 2.8 times greater than CeO 2 and MnFe 2 O 4 respectively. Here, the study provides a clear insight into the photocatalytic mechanism of the p-n type NCs, which exhibited efficient charge transfer and improved mobility. The scavenging assay and ESR analysis have explicated the major role of •OH radicals as the dominant reactive oxygen species on the photocatalytic degradation of MB dye. The photocatalytic efficiency of CeO 2 /MnFe 2 O 4 NCs-1:1 for MB dye degradation was found to be 86%. The results expressed almost similar degradation efficiency till the 6th cycle and the structural integrity of the NCs was found to be intact even after the photodegradation. Additionally, a predictive degradation pathway for MB was elucidated by Fukui function-based DFT analysis. The anti-microbial activity of the prepared samples was investigated against S. aureus and E. coli. Hence, the fabricated CeO 2 /MnFe 2 O 4 NCs-1:1 was concluded with the obtained results and it has been observed to be a potential candidate as an efficient photocatalyst for the elimination of toxic organic pollutants. [Display omitted] • CeO 2 /MnFe 2 O 4 NCs was synthesized by sono-chemical coprecipitation method. • The CeO 2 /MnFe 2 O 4 NCs showed outstanding visible-light photocatalytic activity. • The NCs demonstrates good photostability and reusability. • The hydroxyl radical was responsible for the enhance photocatalytic activity. [ABSTRACT FROM AUTHOR]

Mn-based photocatalyst and antimicrobial agent was synthesized by ultrasonic-assisted co-precipitation method by keeping MnO 2 as active compound and Al 2 O 3 was adopted as catalyst support. XRD and HRTEM analysis verified the co-existence of MnO 2 and Al 2 O 3 and the crystalline nature of NCs. The XPS and EDAX revealed the chemical states of elements namely Mn2p, Al2p and O1s. The presence of Mn–O and Al–O–Al bonds were noted through FTIR. The photon absorption ability of NCs in visible region was favoured by the energy bandgap of 2.51 eV. Photoluminescence revealed that the charge carriers in NCs showed an improvement in life time. The NCs exhibited enhanced photocatalytic effect due to its synergetic effect and the photocatalytic performance can be ordered as MnO 2 /Al 2 O 3 > MnO 2 > Al 2 O 3. The enhancement in photocatalysis rate in NCs was attributed by the formation of heterostructure and it prevent the recombination of charge carriers. The OH· radical was the dominant species in dye degradation. The NCs showed high photostability and recyclability, and almost same photocatalytic activity preserved even after sixth recycle. In addition to that, the antimicrobial activity of MnO 2 /Al 2 O 3 was demonstrated to be efficient in their action against the strains of gram positive and gram negative bacteria than that of the individual MnO 2 and Al 2 O 3 NPs. Thus, this multifunctional MnO 2 /Al 2 O 3 can be used as an efficient candidate for the photocatalytic degradation of toxic dyes and an antimicrobial agent. • MnO 2 –Al 2 O 3 NCs was constructed by chemical co-precipitation method. • The rate of photodegradation of MB by NCs was 6 times higher than Al 2 O 3 NPs. • Photoluminescence study revealed the reduced recombination rate of e−/h+ pairs. • The OH· radical was the dominant species in dye degradation. • The nanohybrid exhibited excellent antibacterial activity. [ABSTRACT FROM AUTHOR]