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This work presents an application perspective of recently developed, novel green synthesized self-heteroatom doped N-carbon dots (N-CDs) derived from biomass pumpkin seeds, possessing an energy gap of 2.35 eV and an unremarkable quantum efficiency of 65.5%, besides a graphitic carbon structure they are doped with various metal and nonmetal ions and an overall size distribution of 5-8 nm. Here we have used them as a novel photocatalyst by mixing them with widely known photocatalyst titanium dioxide, thereby enhancing the overall photocatalytic efficiency of the amalgam of both materials. Further, this novel amalgam of Carbon dots has demonstrated a well-distinguished FTIR, XRD, and UV absorbance and emission wavelength spectra, and displayed a broad absorbance wavelength spectra in lower energy region, hence more efficient compared to pure Titanium dioxide. Thus the composite of TiO2/N-CDs degraded Congo red dye in a short duration of 18 minutes, illuminated under UV light, and has shown 90% degradation efficiency. However, only 40% degradation was shown by pure N-CDs. Further, we have used these Carbon dots as a sensing material for the detection of heavy metal ions and the results have demonstrated a good detection limit of the heavy metal Hg2+ ions among other tested metal ions, owing to its excellent selective and sensitive property of fluorescent quenching analysis, resulted in the creation of non- fluorescent centers, effective charge transfer and overall energy transfer, with a minimum detection threshold limit of 20 nM.

Recent years have seen many attempts to increase the efficiency and reduce the pressure drop of High-Efficiency Particulate Air Filter (HEPA) filters in removing microorganisms through shape change and the use of photocatalysts. This study is the first scoping review of the effects of photocatalysts on increasing the efficiency of HEPA filters in the elimination of airborne microorganisms.

PubMed, Scopus, Irandoc, and Magiran databases were searched for relevant articles. Based on select keywords and the study objectives and applying the inclusion and exclusion criteria, eight from a total of 315 articles were identified, two of which were typical in the review of efficiency and pressure drop. These articles investigated the effect of photocatalyst and filter shape on the efficiency and pressure drop of HEPA filters.

These studies were released from 2000 to 2021. TiO2, with its long-term interactions with microorganisms, the attack of superoxide radicals (O2•−), and the release of K+, RNA, proteins, and other essential components will cause their destruction. Ultraviolet rays at a wavelength of 254 nm remove bacteria on the surface of the filter. The synergy of the inherent ability of UV radiation with TiO2 through nucleic acid and protein damage in microorganisms and the generation of oxidative radicals increases the efficiency of HEPA filters compared to either one alone.

The photocatalysts with ultra-violet rays on the HEPA filter can reduce the problem of microorganism growth and increase indoor air quality.

Nowadays, due to the increasing problems of microbial resistance, scientists are searching for the safest and most effective way to fight them. The colloidal silver (Ag) and titanium dioxide (TiO2) nanoparticles can effectively fight against many bacterial microorganisms. Therefore, the purpose of this study was to investigate the antibacterial and cytotoxic properties of Ag and TiO2 nanoparticles, against Shigella dysenteriae and Staphylococcus aureus.

In this study, Ag and TiO2 nanoparticles were synthesized, and the minimum inhibitory and bactericidal concentrations (MIC & MBC) were determined. In addition, the cytotoxicity of these agents was evaluated on Hu02 fibroblast cell line.

We found that the MIC and MBC for Ag and TiO2 nanoparticles were similar (12.5 µg/ml) against S. aureus, while the MIC’s for Ag and TiO2 against S. dysenteriae were found to be 12.5 and 25 µg/ml. In addition, the MBC’s for Ag and TiO2 against S. dysenteriae were 25 and 50 µg/ml. Based on the cytotoxicity tests, the cell viability percentage after 48 hours of exposure to TiO2 was higher than that of Ag (0.025 µg/ml).

The Ag and TiO2 nanoparticles demonstrated good antibacterial properties while they had low toxicity against the Hu02 fibroblast cell line.

 The International Agency for Research on Cancer (IARC) identified formaldehyde as a carcinogen in 2004, yet formaldehyde is widely used in health care settings and various industries. In recent years, photocatalytic oxidation has been developed as a potential technique for removing pollutants arising from organic chemical agents and consequently promoting the health indices. This study investigated the effect of operational factors in optimizing formaldehyde removal from the air using Ag3 PO4 /TiO2 photocatalyst.

 An experimental study was designed to investigate the effect of operational factors on the efficiency of formaldehyde degradation. The variables investigated in this study include pollutant retention time, initial pollutant concentration and relative humidity. Sol-gel method was used to synthesize the nano-composite photocatalyst. An ideal experimental design was carried out based on Box-Behnken design (BBD) with response surface methodology (RSM). The sample size in this study includes all the glasses coated with Ag3 PO4 /TiO2 photocatalyst.

 The maximum formaldehyde degradation of 32% was obtained at the initial concentration of 2 ppm, 20% relative humidity, and 90 minutes of retention time. Based on the statistical results, the correlation coefficient of the present study for the impact of operational factors on formaldehyde degradation was 0.9635, which means that there is only 3.65% probability of error in the model.

 The operational factors examined in this study (retention time, relative humidity, and initial formaldehyde concentration) were significantly influential in the degradation efficiency of formaldehyde by the photocatalyst. Due to the high exposure of employees and clients of health and treatment centers to formaldehyde as a carcinogenic substance, the results of this study can be used in ventilation systems to remove environmental pollutants in health care centers and other occupational settings.

Compounds containing dye are toxic, carcinogenic and mutagenic for aquatic organisms and lead to mutagenicity, carcinogenicity, and dysfunction of human beings’ kidney, liver, brain, reproductive system and central nervous system. Advanced oxidation processes can remove pollutants faster than other processes due to active hydroxyl radical production. This study was aimed at investigating feasibility of dye removal using UVA/TiO2 process.

This study was done in a batch reactor and the effects of initial dye concentrations, TiO2 nanoparticles dosage, time, pH and interference compounds on efficiency of dye degradation was investigated. The Daphnia Magna as bioassay test and biodegradability index (BOD5/COD rate) were used for detoxification assessment.

The D.Y 50 dye effluent degradation at pH 2, 20 mg/l initial dye concentration and 1 g/l TiO2 catalyst was (lnC0/C= 1.4), (lnC0/C= 3) and (lnC0/C= 2.9) respectively. Dye removal rate by 50 mg/l COD concentration was (88%), Daphnia Magna mortality rate after maximum contact time (96 h) decreased from 96.7% to 43.3% and biodegradability index increased from 0.25 to 0.68.

Parkinson’s disease (PD) is a severely debilitating disease for which no suitable treatment has been foundso far. In recent years, nanoparticles (NPs) have shown therapeutic potential in PD. Thus, in the current research, forthe first time, we investigated the effects of vitamin E and TiO2 nanoparticles (TiO2-NPs) on a rat model of PD. In this experimental study, after preparation and induction of PD, rats were administratedwith vitamin E and TiO2-NPs. One day after receiving the last dose of treatments, rats were killed and substantianigra was extracted from the brain and its cell suspension was prepared. In each group, female rats were mated, andafter confirmation that the female rats were pregnant by vaginal smear test, the fetus was removed. Cell viability wasstudied by the MTT method and apoptosis, and necrosis were studied by the flow cytometry technique. Also, after RNAextraction and cDNA synthesis, the expression of Bcl-2 and circRNA 0001518 genes were studied using the real timepolymerase chain reaction (RT-PCR) technique. For analyzing the data, two-way ANOVA was used. The results showed a sharp decrease in cell viability in female PD rats and fetuses resulting from PD femalerats. Vitamin E treatment showed the greatest effect on increasing cell viability. Decreased expression of the Bcl-2 geneand increased expression of circRNA 0001518 were observed in PD conditions. Administration of vitamin E may be a good option for reducing PD-induced cell death.

In the current study, for the first time, an innovative hydrothermal method was proposed for the synthesis of TiO2/WO3 heterojunction nanocomposite from the combination of TiO2 nanorod, and WO3 nanoflakes. Because of environmental issues arising from the vast use of insecticides, this nanocomposite photocatalyst was applied for the first time for photocatalytic degradation of Nitenpyram insecticide under visible light irradiation. The prepared nanocomposite was fully characterized by XRD, FESEM, DRS, PL, and Mott-Schottky analysis. The results revealed that the heterojunction sample had the best photocatalytic performance. The enhanced photocatalytic activity of this heterojunction is attributed to the decrease of the charge carrier’s recombination rate and enhanced visible light harvesting. Moreover, based on the radical trapping experiments and Mott-Schottky calculations, hydroxide radical was determined as the main active species for decomposition of Nitenpyram insecticide, and type II charge transfer mechanism was revealed to be responsible for the enhanced photocatalytic performance, which charge transfer between the two semiconductors results in the decreasing of the charge carrier’s recombination rate.

Temperature changes cause testicular dysfunction. It has been observed that testicular hyperthermia leads to oxidative stress and as a result a severe reduction in testicular parameters. Causes a severe reduction in Sperm parameters to become oxidative due to stress. Recently, natural plant materials and magnetic nanoparticles have been considered. In the internal mitochondrial apoptosis pathway, gen bcl2 is a target of miR455.

The present study aimed to investigate the effects of titanium dioxide nanoparticles and improve their impacts by using the antioxidant curcumin on sperm parameters by investigating changes in expression miR455 in response to temperature-induced stress in scrotal hyperthermia rats.

After preparation, the rats were placed in a hot water bath at 43°C. for 30 minutes for six consecutive days. The rats were then divided into eight groups. We used TiO2 nanoparticles at a concentration of 0.03 mg/kg of body weight and curcumin at a concentration of 0.02 mg/kg of body weight. After killing the animals, such parameters of sperm as viability, concentration, motility, and morphology of spermatozoa were studied. RNA extraction and cDNA synthesis were performed using appropriate kits. A gene primer was designed and RT-PCR was used to assess gene expression. The t-test and ANOVA were used to examine differences between different groups. Data analysis was performed using Prism8 software and SPSS version 26.

The results showed that miR455 expression was lower in the treatment groups and was associated with curcumin (P < 0.05). A positive effect of curcumin on improving sperm parameters in rats with scrotum hyperthermia and a negative and toxic effect of TiO2 nanoparticles were shown. However, a significant improvement in sperm parameters was observed when rats were given TiO2 nanoparticles along with curcumin.

The changes in the expression miR455, shown in curcumin have controlled the damage to TiO2 nanoparticles. It seems that miRNA455 can be used as a marker to predict sperm health status. So Curcumin can play a protective role in reducing the toxic effects of testicular hyperthermia as well as titanium dioxide nanoparticles.

The 1-Naphthol, one of the derivatives of naphthalene, is the most significant industrial chemical that is widely used in the production of dyes, pharmaceuticals, and biochemical processes.

In the present study, N, S-doped TiO2 thin film immobilized on silica sulfuric acid (SSA) glass microspheres (MS) was investigated as a novel high efficient photocatalyst. The N, S-doped TiO2 immobilized on SSA was fabricated using a simple modified sol–gel process. Its photocatalytic activities were then assessed using 1-naphthol solution in the presence of visible light. The physico-chemical properties of photocatalyst were characterized using energy-dispersive X-ray (EDX), scanning electron microscope (SEM) images and X-ray diffraction (XRD) pattern.

According to the obtained results, the optimal pH, time, concentration, and removal efficiency of 1-naphthol for N, S-doped TiO2 /SSA was 5, 50 minutes, 25mg/l and 92.12%.

The present study confirms the usability of the immobilized N, S-doped TiO2 on SSA glass MS as a novel, effective, and efficient technique for treatment of wastewater containing 1-naphthol under visible light.

In this work we are suggesting a method to reduce the amount of metal nitrates used in industrial and agricultural applications with the help of photocatalytic effect. Also, the work discusses how the residual amount of metal nitrates in the soil can be made useful through the same effect. Though metal nitrates like ferric nitrate and nickel nitrate shows characteristic absorption in the UV region, what we observed is an enhancement in this UV absorption when we treated this metal nitrates with Titania Tenorite nanocomposite due to its photocatalytic action. This absorbance enhancement property is an indication of increase in concentration of the metal nitrates in the solution with light irradiation. The increase in M–OH bonds owing to the action of the nanocomposite in the presence of light is the reason by which metal nitrates absorption increases. In precise a tiny amount of metal nitrates is needed for any practical use as it can automatically increase its concentration in presence of the nanocomposite by photocatalytic reaction. This will reduce the disposal of unwanted amount of metal nitrates into the surrounding especially water bodies. Also, the residue amount in the soil can act as UV absorbers. Thus, the combination of the metal nitrates with the nanocomposite can be made used for environmental remediation where the metal nitrates are used in large quantities.

In this study, the TiO2 nanoparticles were supported on Y-type zeolite as a new photocatalyst and used to degrade Acid Red 18 in aqueous media. The nano photocatalyst was synthesized by coprecipitation procedure and characterized by Fourier transfer infrared (FTIR), field emission scanning electron microscopy (FE-SEM), and X-ray powder diffraction (XRD). The central composite design (CCD) was employed for experimental design. The effect of operative variables including contact time, photocatalyst dosage and pH were investigated. The ANOVA (analysis of variance) studies displays the second-order regression model and a high determination coefficient value (R2 = 0.9953, R2pred = 0.9642, R2adj = 0.9910) for the destruction of AR18 was obtained. The contour plots were applied to study the shares of each variable and their interactions on the degradation of AR18. The optimal circumstances predicted by the model were as the following: the catalyst concentration at 0.88g/L, pH at 6.5, and contact time in 125 min. In this situation, the predicted and actual dye removal were 98.5% and 96.3%, respectively. The removal of COD (chemical oxygen demand) after 125 min was 53% indicating, the notable performance of photocatalyst in mineralization of AR18.

Malachite green (MG) is widely used as a fungicide, Bactericide parasiticide in the aquaculture industry, as a food additive, medical disinfectant, and also, as a dye for materials such as silk, leather, paper, etc. In this study, the photocatalytic removal of MG from aqueous solutions using TiO2-containing nanocomposites was reviewed.

In this study, four databases (PubMed, Web of Science, ScienceDirect, and Scopus) were systematically searched to collect studies on the decomposition of MG using nanocomposites containing TiO2 under UV light radiation.

In total, 10 related and eligible studies were selected. Based on the results, TiO2 was doped with iron, Sn, Ag, Si, and Ni. The highest percentage of photocatalytic decomposition for MG was observed in Sn > Ni > Ag > Fe > Si. The removal efficiency of MG in the studied papers was between 75%-100%.

Recombinant nanocomposites had a higher dye removal percentage than uncombined ones because they play an important role in the photocatalytic process of dye, by producing free radicals.

Sol–gel method was applied for synthesis of TiO2 nanoparticles in the existence of different volumes of ethanol (10–50 mL) with the purpose to find optimized synthesis conditions. Also, nickel doped TiO2 nanoparticles (Ni/TiO2 molar ratio: 0.1-1.0%) were prepared by the similar technique but in the existence of 10 mL ethanol and heated at different temperatures (300 °C –600 °C). XRD, SEM/EDX, UV-Vis DRS, FTIR and Raman spectroscopy were applied to identify the structural and morphological characteristics of the as-synthesized samples. XR diffraction results verified that TiO2 samples prepared with various volumes of ethanol (10–50 mL) consist of anatase and brookite phases up to 500 °C and rutile phase at 600 °C. The intensity of brookite diffraction decreased with the increase of calcination temperatures. Also, the low ethanol volume favored for formation of rutile phase at 600 °C. The addition of Ni(II) during the preparation of TiO2 nanoparticles prevented the formation of rutile phase. The undoped samples were synthesized with 10 and 20 mL ethanol and treated at 500 °C displayed the best catalytic performance for photocatalytic treatment of E 131 VF dye solution (rate constant: 0.051 and 0.061 (a.u) respectively). Ni doped TiO2 samples displayed lower photoactivity and rate constant.

Titania has been one of the promising alternatives in treating environmental pollution issues and was considered in various applications due to its flexible behaviour. Many studies have been conducted to test its phase-changing properties and adaptive ability such as calcination process, and metal and nonmetal modification using mono-doped or co-doped elements. In the present study, the photocatalyst was developed from embedment with activated carbon (AC) followed by co-doping of Cu2+ and Fe3+ metal ions. The photocatalyst was characterized by XRD, BET and FESEM. The synthesized photocatalyst was tested in the photocatalytic degradation system for ionic liquid (IL) at the optimized parameters which includes solution pH = 6, [photocatalyst] = 1 g/L and [H2O2] = 0.75 ml/L. The co-doped product exhibited a smaller crystalline sizes as compared to bare TiO2. In addition, copper and iron dopants are well dispersed into the TiO2 lattice as no additional phases were detected. Maximum degradation of 77% of 0.11mM IL was recorded in the Cu:Fe-TiO2/AC system after 240 min of visible light irradiation. The system’s efficiency in terms of tested photocatalysts is in the order of P25 < TiO2 < TiO2/AC < Cu:Fe-TiO2/AC, respectively.

Microcystin-leucine arginine (MC-LR) is a toxin with harmful effects on the liver, kidney, heart, and gastrointestinal tract. So, effective removal of MC-LR from water resources is of great importance. The aim of this study was to remove microcystin-LR (MC-LR) from aqueous solution by Titanium Dioxide (TiO2).

In the present study, TiO2, as a semiconductor, was used for photodegradation of MC-LR under ultraviolet light (UV). The Response Surface Methodology was applied to investigate the effects of operating variables such as pH (A), contact time (B), and catalyst dose (B) on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC).

The results showed that single variables such as A, B, and C had significant effects on MC-LR removal (pvalue < 0.05). In other words, increase of the contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The analysis of variance showed that BC, A2, and C2 variables had a significant effect on the MC-LR removal (pvalue < 0.05). Finally, the maximum removal efficiency of MC-LR was 95.1%, which occurred at pH = 5, contact time = 30 minutes, and catalyst dose = 1 g/l.

According to the findings, TiO2, as a photocatalyst, had an appropriate effect on degradation of the MC-LR.

The increase of bacterial resistance to common antibacterial agents is one of the major problems of health care systems and hospital infection control programs. In this study, antimicrobial activity of titanium dioxide (TiO2) and zinc oxide (ZnO) nanoparticles (NPs) was investigated against E. coli, Salmonella enteritidis, Listeria monocytogenes, and Staphylococcus aureus pathogenic bacteria by determining sensitivity coefficient and kinetics of bacterial death.

Antimicrobial tests were performed with ~106 CFU/mL of each bacterium at baseline. At first, minimum inhibitory concentration (MIC) was concluded by the dilution method and then, death kinetic and susceptibility coefficient of NPs suspensions was determined at 0 to 360 min. treatment time.

The results of this study revealed that, the highest susceptibility was observed for L. monocytogenes (Z=0.025 mL/μg) to TiO2 NPs, whereas the lowest susceptibility was obtained in the reaction of ZnO NPs with S. enteritidis (Z = 0.0033 mL/μg). The process of bacterial death in NPs suspension was assumed to follow first-degree kinetic and the survival ratio of bacteria decreased by the increase in treatment time. An increase in the concentration of NPs was seen to enhance the bactericidal action.

Results showed that L. monocytogenes had higher sensitivity compared to S. enteritidis. The results of this study also demonstrated that TiO2 NPs have a strong antimicrobial effect in comparison with ZnO NPs and it could be employed to aid the control of pathogenic bacteria.

Volatile organic compounds (VOCs) are one of the main group of air pollutants. Photocatalytic oxidation is one of the destructive methods for gaseous pollutants and has been received more attention in the past years. In this study investigated the comparison of the toluene removal efficiency by Photocatalytic Oxidation of Toluene by ZnO/SiO2 and TiO2/SiO2. In this study, the effect of parameters such as the amount of relative humidity, initial concentration of pollutant, the apparent speed of gas and the minimum speed of fluidizing of bed on the process of photocatalytic oxidation of Toluene is examined by comparison between TiO2/SiO2 and ZnO/SiO2 catalysts in a fluidized bed reactor. as it was explained, by absorption of water molecules on the surface of the catalyst and converting them to hydroxyl active radicals, these radicals act as a pushing factor in the reaction. The study also showed that an increase in the relative humidity in the 15–45% range would increase the efficacy of toluene oxidation. Conversion percentages between TiO2/SiO2 and ZnO/SiO2 catalysts were not significantly different (pv>0.05), while the reaction rate of ZnO/SiO2 catalyst was higher than TiO2/ SiO2 catalyst (pv<0.05). In the study of the interaction between the apparent velocity variables, initial concentration of toluene and loading of zinc oxide and titanium dioxide, only the interaction between two gas velocity variables and initial concentration of toluene was significant. The results showed that ZnO/SiO2 catalysts generally have a larger efficacy than TiO2/SiO2, presumably because ZnO/SiO2 has more active sites. Additionally, the ZnO/SiO2 catalysts offer better fluidity than TiO2/SiO2. The photo catalytic transformation rate of the pollutant is relatively low, as the optimum humidity level for appears to be 45%.

In this study, TiO2/Fe3O4 and TiO2/Fe3O4/MWCNT as a new magnetic nanophotocatalytic materials were synthesized. For this, TiO2 nanoparticle were fixed on an inert surface by sonochemical method. X-ray Diffraction (XRD), scanning electron microscopy (SEM), UV-Vis diffuse reflectance spectroscopy (DRS), vibration sample magnetometry (VSM) were used to characterize the magnetic nanocomposites. SEM analysis indicated that TiO2 and Fe3O4 nanoparticles were adhered to MWCNT. Ability of the nanocomposites to remove organic pollutants were investigated by photodegradation of Acid Red 14, Acid Blue 19, Reactive Red 77, and Methyl Orange dyes simulated conditions similar to sunlight. Furthermore, the removal efficiency of AR14 were investigated under direct sunlight irradiation, with an initial concentration of 50 mg/L by TiO2, TiO2/Fe3O4 and TiO2/Fe3O4/MWCNT nanocatalysts were 89.83, 21.19 and 86.27, respectively. According to the results, addition of carbon nanotubes to the TiO2/Fe3O4 magnetic nanocomposite, increased the efficiency of AR14 photodegradtion through change in energy gap visible waves and the scavenging role of carbon nanotubes. Also, The reusability of nanocomposites was assessed in five consecutive cycles of 6 hours, The results showed that after 5 cycles the degradation rate decreased only 7.79 %.

This study was conducted to evaluate sodium dodecyl benzene sulfonate removal using electrocoagulation/flotation and photocatalytic nano-TiO2 slurry systems. The parameters which are effective on the surfactant removal were investigated and optimized. Electrocoagulation/flotation system included meshed and mono-polar stainless steel electrodes which installed horizontally. According to the results, after 60 minutes in pH of 8, electrodes distance of 1 cm, initial SDBS concentration of 750 mg/L, SDBS and COD removal rates were achieved to 93.54 and 90%, respectively. In photocatalytic system, during 48 h, SDBS and COD removed 98.7 and 95%, respectively, while pH was around 8, initial concentration of SDBS was 300 mg/L and nano-TiO2 particles concentration was 0.5 mg/L. In the hybrid system, after 12 minutes, SDBS concentration reached to 329 mg/L which entered to the photocatalytic system that resulted in SDBS and COD removal efficiency of 99 and 96.27%, respectively. Compared to the single systems, by using the hybrid system, the removal efficiencies were improved.

In this work, we studied the effect of various amounts (0.2-1.2 % mole ratio) of Cu doping to TiO2 nanoparticles (Cu/TiO2) on the photocatalytic removal efficiency of the food colorant E 131 VF. Two series of doped TiO2 (P25) photocatalysts were prepared in two different media (50%ethanol-50%acetone and 5% surfactant (Tween 20)-95%H2O) by using the impregnation method. The prepared samples were characterized by XRD, FTIR, Raman, diffuse reflectance spectroscopy and SEM/EDX analyses. The XRD results showed that the crystal dimension of TiO2 increased from 23 to 35 nm and rutile/anatase ratio decreased from 16% to 9% after Cu doping in two different media. The photoactivity of TiO2 was reduced in the presence of Cu even at low molar ratio. The photocatalytic degradation rate constant of TiO2 (P25) was 0.24 (au) but it decreased to 0.015 (au) in the presence of the sample containing 0.6% Cu. Several reasons were suggested to explain the dramatic decrease in the activity of the prepared Cu/TiO2samples.