Background: 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.
Methods: 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.
Results: 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%.
Conclusion: 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.

Background: Removing natural organic substances from drinking water sources is necessary to prevent the formation of toxic and carcinogenic disinfection by-products (DBPs). The nano-photocatalytic oxidation process to remove these substances is easier, faster, cheaper, and more efficient than other methods.
Methods: This study investigated the efficiency of the TiO2/UV nano-photocatalytic process in removing humic acid (HA) and fulvic acid (FA) from aqueous solutions. Batch tests were performed to investigate the effect of various parameters such as contact time (15, 30, 45, 60, and 75 minutes), initial pH (4, 7, and 9), initial HA and FA concentration (0.5, 1, 2, 5, and 7 mg/L-1), TiO2 dose (5, 10, 15 and 20 mg/L-1), and different UV irradiation (8 W and 16 W) for the removal of HA and FA from aqueous solutions using TiO2/UV at room temperature (20 ± 3 °C). The equilibrium adsorption data and the standard parameters were evaluated. Data were analyzed using SPSS version 25.
Results: The efficiency of this process in optimal conditions (pH: 4, anatase TiO2: 10 mg/L-1, irradiation time: 60 min, UV = 16 W) for removing humic and fulvic (initial HA concentration: 2 mg/L-1 and initial FA concentration: 5 mg/L-1) was 89% and 92%, respectively. The analysis of the experimental isotherm data showed that in the adsorption process of HA and FA on TiO2/UV, the Langmuir isotherm and the first-order reaction had the best fit with the experimental data.
Conclusion: TiO2/UV nano-photocatalytic process is suitable for the photo-degradation and removal of HA and FA in aqueous solutions.

Background: SARS-CoV-2, the causative agent of the COVID-19 pandemic, spreads through both direct and indirect pathways. Among the latter, surface contamination is a significant concern due to the virus’s prolonged viability on surfaces. There is ongoing discussion over the impact of environmental surface contamination, especially in light of the introduction of novel viral types. The present study aimed to examine the extent of environmental surface contamination across different hospital wards and evaluate the effectiveness of disinfectants in inactivating the virus.
Methods: The samples were collected from critical areas in a hospital, both pre-disinfection (n = 40) and post-disinfection (n = 17), using reverse transcription-polymerase chain reaction (RT-PCR) to detect SARS-CoV-2.
Results: The findings indisputably confirm the presence of SARS-CoV-2 on swab samples from frequently-touched surfaces. Notably, 10 samples were virus-positive before disinfection, highlighting persistent viral contamination in vital hospital zones.
Conclusion: This study underscores the critical role of environmental surface contamination in SARSCoV-2 transmission, particularly in healthcare settings. Detecting the virus on frequently-handled surfaces underscores the urgent need for rigorous and frequent surface disinfection. Effective surface disinfection remains a rapid, straightforward, and practical strategy to mitigate virus transmission to healthcare workers and patients. These findings hold significant implications for infection control, particularly amid emerging virus variants. They emphasize the need to maintain stringent hygiene and disinfection practices within healthcare facilities to combat the spread of COVID-19.

Background: The ongoing COVID-19 pandemic has emphasized the significance of understanding the role of commonly contacted surfaces in the virus circulation. This study aimed to examine the contamination levels of the COVID-19 virus on repeatedly manipulated surfaces within urban areas.
Methods: We have conducted a study based on a systematic review and used it to choose a methodology, compare, and interpret the data. In this research, 22 samples were obtained from diverse surfaces in the environment, both before and after the implementation of sanitizer protocols.
Results: The results obtained from sampling and polymerase chain reaction (PCR) analysis conducted before sanitizers revealed that out of the 22 samples, 4 cases (18.18%) tested positive. However, none of the 22 samples showed any positive cases following the sanitizer process.
Conclusion: By conducting a comprehensive analysis, this research contributes to the existing body of knowledge regarding the effectiveness of sanitizer measures in mitigating the spread of the virus in urban environments.