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Antibiotics are pervasive contaminants in aqueous systems that pose an environmental threat to aquatic life and humans. Typically, antibiotics are developed to counteract bacterial infections; however, their prolonged and excessive use has provoked unintended consequences. The presence of excessive amounts of antibiotics and anti-inflammatory, anti-depressive, and contraceptive drugs in hospital and industrial wastewater poses a significant threat to the ecosystem, with groundwater containing drug concentrations of <1 mg/L to hundreds of µg/L. According to the literature, 33,000 people die directly from drug-resistant bacterial infections in Europe annually, which costs EUR 1.5 billion in health care and productivity loss. Consequently, the continuous spread of antibiotics in the ecosystem has led to greater interest in developing a sustainable method for effective antibiotic removal from wastewater. This critical review aims to present and discuss recent advances in the photocatalytic degradation of widely used drugs by ZnO-based nanostructures, namely (i) antibiotics; (ii) antidepressants; (iii) contraceptives; and (iv) anti-inflammatories. This study endows a comprehensive understanding of the degradation of antibiotics using ZnO-based nanomaterials (bare, doped, and composites) for effective treatment of wastewater containing antibiotics. In addition, the operational conditions and mechanisms involved during the photocatalytic degradation process are systematically discussed. Finally, particular emphasis is devoted to future challenges and the corresponding outlook with respect to toxic effects following the utilization of ZnO-based nanomaterials.

The development of advanced materials for the removal of heavy metal ions is a never-ending quest of environmental remediation. In this study, a facile and cost-effective approach was employed to synthesize copper ferrite (CF) and copper ferrite/reduced graphene oxide (CG) by microwave assisted combustion method for potential removal of barium ions from aqueous medium. The physiochemical characterizations indicated the formation of magnetic nanocomposite with an average crystallite size of CF and CG is 32.4 and 30.3 nm and with specific surface area of 0.66 and 5.74 m2/g. The magnetic results possess multidomain microstructures with saturation magnetization of 37.11 and 33.84 emu/g for CF and CG. The adsorption studies prove that upon addition of rGO on the spherical spinel ferrite, the adsorption performance was greatly improved for CG nanocomposite when compared with the bare CF nanoparticles. The proposed magnetic adsorbent demonstrated a relatively high Ba2+ adsorption capacity of 161.6 mg·g-1 for CG nanocomposite when compared to 86.6 mg·g-1 for CF nanoparticles under optimum conditions (pH=7;T=25°C). The pseudo-first-order (PFO), pseudo-second-order (PSO), and Elovich models were fitted to the kinetic data, the yielded R2 value of 0.9993 (PSO) for CF and 0.9994 (PSO) for CG which is greater than the other two models, which signify that the adsorption process is chemisorption. Thermodynamic studies show that barium adsorption using CF and CG adsorbents is endothermic. The as-fabricated CuFe2O4/rGO nanocomposite represents a propitious candidate for the removal of heavy metal ions from aqueous solutions.

Multifunctional core@shell nanoparticles have been synthesized in this paper through 3 stages: NiFe2O4 nanoparticles by microwave irradiation using Pedalium murex leaf extract as a fuel, core@shell NiFe2O4@TiO2 nanoparticles by sol-gel, and NiFe2O4@TiO2@rGO by sol-gel using preprepared reduced graphene oxide obtained by modified Hummer’s method. XRD analysis confirmed the presence of both cubic NiFe2O4 spinel and tetragonal TiO2 rutile phases, while Raman spectroscopy analysis displays both D and G bands (ID/IG = 1.04) associated with rGO. Morphological observations by HRTEM reveal a core-shell nanostructure formed by NiFe2O4 core as confirmed by SAED with subsequent thin layers of TiO2 and rGO. Magnetic measurements show a ferromagnetic behavior, where the saturation magnetization drops drastically from 45 emu/g for NiFe2O4 to 15 emu/g after TiO2 and rGO nonmagnetic bilayers coating. The as-fabricated multifunctional core@shell nanostructures demonstrate tunable self-heating characteristics: rise of temperature and specific absorption rate in the range of ΔT = 3–10°C and SAR = 3–58 W/g, respectively. This effectiveness is much close to the threshold temperature of hyperthermia (45°C), and the zones of inhibition show the better effective antibacterial activity of NTG against various Gram-positive and Gram-negative bacterial strains besides simultaneous good efficient, stable, and removable sonophotocatalyst toward the TC degradation.

This study was aimed at determining the cytotoxic efficacy of graphene oxide (GO) and thiourea-reduced oxide (T-rGO) nanosheets against human prostate cancer cells and their antibacterial activity against E. coli mastitis. X-ray diffraction, Raman spectroscopy, Fourier transformed infrared spectroscopy, and scanning electron microscopy were used to study the physicochemical properties of the fabricated GO and T-rGO. The cytotoxicity of GO and T-rGO in human prostate cancer cells was examined using cell survival test, DNA laddering, and cell cycle analysis. The antibacterial effectiveness of GO and T-rGO was tested using E. coli mastitis. The study revealed that cell viability was lowered by GO and T-rGO in a concentration-dependent trend. The production of reactive oxygen species and hydroxyl radicals was found to increase following the treatment. DNA was harmed because of oxidative stress, causing laddering. Both GO and T-rGO demonstrated good antibacterial activity against E. coli mastitis. The findings of this research work provide insightful information about functional graphene derivatives for potential biomedical applications, primarily cancer treatment.

. In this study the effect of annealing time is confirmed to alter the morphology (shape and size) of magnesium ferrite nanoparticles (MgFe 2 O 4 ) synthesized by autoclave route, employing ferric and magnesium nitrate salts as precursors. Annealing was applied at 1000 ° C for different durations (2, 30 and 60 h) and Rietveld refinements of X-ray diffraction patterns confirm the formation of pure spinel phase and show that the annealing time has a dominant effect on the crystallite size as it increases from 29 up to 89 nm for 2 to 60 h, respectively. Scanning electron microscopy observations confirm that longer annealing time enhances particle growth, in agreement with the crystallite size obtained by X-ray diffraction analysis. Room temperature magnetic measurements reveal a ferromagnetic behavior with a saturation magnetization (M s ) ranging from 25.84 emu/g for annealing at 2h and 29.49 emu/g at 60 h. Self-heating characteristics under an alternating current (AC) magnetic field of 17mT and frequency of 331 kHz were investigated for hyperthermia applications using Magnetherm from Nanotherics. Temperature-time curves indicate that the as-prepared MgFe 2 O 4 nanoparticles show a considerable heating rate, with a maximum temperature of 48 ° C in a very short period of time of 15 min and specific absorption rate (SAR) of 19.23 W/g, when annealed for 60 h.

In this study, we used a two-stage process and phosphoric acid to thermochemically transform waste biomass rice straw into porous carbon (PC) for the preparation of high-performance supercapacitor electrodes. The morphological and chemical characteristics of PC were investigated by X-ray diffraction, scanning electron microscopy, surface area, and porosity analyses by the BET (Brunauer, Emmett, and Teller) nitrogen adsorption method, Fourier transform infrared spectroscopy. The modification process leads to the increase in the specific surface area and pore size of PC. The dc conductivity of the samples determined at room temperature was found to increase from 16.1 × 10 −5 to 10.16 × 10 −3  Ω −1  cm −1 . The samples showed good electrochemical property with specific capacitance possessing in the range of 56–112 F/g. It was found that the carbonization temperature plays a crucial role on the evolution of structural and electrochemical properties of porous carbons. These porous carbons which show a particular large reversible capacity are proved to be promising electrode materials for high-rate and high-performance supercapacitors.

In this study, MgFe 2 O 4 nanopowders were synthesized through two different methods, sol–gel method (SG) and modified sol–gel with Ammonia (MSG-A). The influence of synthesis route was investigated in terms of phase stability, pores size and surface area, magnetic properties and uptake of Ni and Cd metals from aqueous solution. Rietveld refinements of x-ray diffraction patterns confirmed the formation of single spinel phase for SG sample, while minor impurity was detected for SGM-A sample (few amount of MgO). The crystallite size was found to be sensitive to the preparation method; it ranges from 4 nm for SG to 15 nm for MSG-A. Magnetization experiment at room temperature showed ferromagnetic behavior with a saturation magnetization ( M s ) ranging from 5.39 emu/g for SG to 9.93 emu/g for MSG-A. Preliminary results showed that SG and MSG-A samples are efficient adsorbent for Ni and Cd metal ions from aqueous solution. Maximum quantity of 62.67 and 61.2 mg of Ni(II) and 36.49 and 32.84 mg of Cd(II) was adsorbed per gram of MgFe 2 O 4 synthesized by SG and MSG-A, respectively.

This study demonstrated the effective reduction of graphene oxide (GO) by employing thiourea as a reducing and stabilizing agent. Two fungi (Aspergillus flavus and Aspergillus fumigatus) were used for anti-fungal assay. Cell viability, cell cycle analysis, DNA fragmentation, and cell morphology were assessed to determine the toxicity of thiourea-reduced graphene oxide (T-rGO) on human lung cancer cells. The results revealed that GO and T-rGO were hazardous to cells in a dose-dependent trend. The viability of both A. fumigatus and A. flavus was affected by GO and T-rGO. The reactive oxygen species produced by T-rGO caused the death of A. flavus and A. fumigatus cells. This study highlighted the effectiveness of T-rGO as an antifungal agent. In addition, T-rGO was found to be more harmful to cancer cells than GO. Thus, T-rGO manifested great potential in biological and biomedical applications.

The current research focuses on the fabrication of water-soluble, reduced graphene oxide (rGO) employing thiourea (T) using a simple cost-effective method, and subsequently examining its anticancer characteristics. The cytotoxicity caused by graphene oxide (GO) and T-rGO is investigated in detail. Biological results reveal a concentration-dependent toxicity of GO and T-rGO in human colon cancer cells HT-29. A decrease in cell viability alongside DNA fragmentation is observed. Flow cytometry analysis confirms the cytotoxic effects. The novelty in this work is the use of raw graphite powder, and oxidants such as KMNO4, NaNO3, and 98 percent H2SO4 to produce graphene oxide by a modified Hummers method. This study demonstrates a simple and affordable procedure for utilising thiourea to fabricate a water-soluble reduced graphene oxide, which will be useful in a variety of biomedical applications.

Nanostructured magnesium oxide (MgO) catalysts were prepared by the coprecipitation method and employed for the transesterification of waste cooking oil using methanol. The X-ray diffraction analysis showed that nanostructured MgO phase was formed at calcination temperature of 500 °C. The mean crystallite size of MgO nanoparticles is 7.86 nm. Fourier-transformed infrared spectroscopy studies confirmed the formation of MgO phase with the characteristic vibrational mode of Mg–O. UV–Vis diffuse reflectance spectroscopy reveals that the energy band gap is around 5.84 eV. The presence of magnesium and oxygen elements was determined from energy-dispersive X-ray analysis. The effect of various parameters such as catalyst loading, methanol-to-oil molar ratio, reaction temperature, reaction time and reusability was investigated. A maximum biodiesel yield of 93.3% was achieved with 2 wt% of MgO nanocatalyst (MO5 sample), methanol/oil molar ratio of 24:1, reaction temperature about 65 °C and reaction time 1 h. The nanocatalyst (MgO) was reused at least for 5 times and thereafter resulted in a decrease in the biodiesel yield. The kinetic study of the transesterification reaction followed pseudo-first-order rate kinetics. The composition of fatty acid methyl ester was determined using gas chromatography–mass spectroscopy.