The unavailability of clean drinking water is one of the significant health issues in modern times. Industrial dyes are one of the dominant chemicals that make water unfit for drinking. Among these dyes, methylene blue (MB) is toxic, carcinogenic, and non-biodegradable and can cause a severe threat to human health and environmental safety. It is usually released in natural water sources, which becomes a health threat to human beings and living organisms. Hence, there is a need to develop an environmentally friendly, efficient technology for removing MB from wastewater. Photodegradation is an advanced oxidation process widely used for MB removal. It has the advantages of complete mineralization of dye into simple and nontoxic species with the potential to decrease the processing cost. This review provides a tutorial basis for the readers working in the dye degradation research area. We not only covered the basic principles of the process but also provided a wide range of previously published work on advanced photocatalytic systems (single-component and multi-component photocatalysts). Our study has focused on critical parameters that can affect the photodegradation rate of MB, such as photocatalyst type and loading, irradiation reaction time, pH of reaction media, initial concentration of dye, radical scavengers and oxidising agents. The photodegradation mechanism, reaction pathways, intermediate products, and final products of MB are also summarized. An overview of the future perspectives to utilize MB at an industrial scale is also provided. This paper identifies strategies for the development of effective MB photodegradation systems.

https://www.mdpi.com/2073-4441/14/2/242/pdf?version=1642404093

Review on Methylene Blue: Its Properties, Uses, Toxicity and Photodegradation

Zinc oxide nanoparticles were prepared using corriandrum sativum leaf extract and zinc acetate dihydrate. It was utilized as a photocatalyst for the degradation of anthracene. The catalyst was characterized by x-ray diffraction, high-resolution transmission electron microscopy, scanning electron microscopy, dynamic scattering light, Raman spectrometry and UV–vis spectrophotometry. The catalyst was used in a bench-scale design for degradation of anthracene. The factors affecting the photocatalytic degradation efficiency, including irradiation time, loading catalyst doses, and initial concentration of anthracene were investigated. The results obtained showed that the photocatalytic degradation efficiency was increased with both the decrease of the initial anthracene concentration and the increase of the photocatalyst doses. The optimum photocatalytic degradation was obtained at pH 7, irradiation time of 240 min and loading catalyst dose of 1000 μg L−1. Under these conditions, the photocatalytic degradation percentage of anthracene was 96%. The byproduct was the much less toxic (9, 10-anthraquinone) and a small amount of phthalic acid as confirmed by gas mass spectrometry and high-pressure liquid chromatography. The kinetic studies revealed that the photocatalytic degradation process obeyed the Langmuir–Hinshelwood model and followed a pseudo-first-order rate expression.

https://iopscience.iop.org/article/10.1088/2043-6262/6/4/045012/pdf

Green synthesis and characterization of ZnO nanoparticles for photocatalytic degradation of anthracene

The balance between economic development and environmental damage is also evident in the problem of pollution and waste management. Increased economic activity, mainly in industrial countries, has ...

Green synthesis: Photocatalytic degradation of textile dyes using metal and metal oxide nanoparticles-latest trends and advancements

Green synthesis of copper nanoparticles using Celastrus paniculatus Willd. leaf extract and their photocatalytic and antifungal properties.

In this study, the photodegradation of methylene blue (MB) dye was performed using urea based graphitic carbon nitride (g-C3N4). Interestingly, it has been observed that the calcination temperature for the synthesis of g-C3N4 along with factors (pH and catalyst loading) influencing the photodegradation process, can make an impactful improvement in its photodegradation activity towards MB dye solution. The concept behind the comparatively improved photoactivity of g-C3N4 prepared at 550 °C was explored using various characterisation techniques like XRD, FTIR, SEM, BET and DRS. The FTIR and XRD patterns demonstrated that synthesis of g-C3N4 took place properly only when the calcination temperature was above 450 °C. The evolution of morphological and optical properties based on calcination temperature led to dramatically increased BET surface area and a decreased optical band gap value of g-C3N4 prepared at 550 °C. The effects of pH conditions and catalyst concentration on the MB dye degradation rate using optimally synthesised g-C3N4 are discussed. The value of the apparent rate constant was found to be 12 times more in the case of photodegradation of the MB dye using g-C3N4 prepared at 550 °C at optimum pH and catalyst loading conditions when compared with g-C3N4 prepared at 450 °C showing the lowest photoactivity potential. Further, high stability of the photocatalyst was observed for four cyclic runs of the photocatalytic reaction. Hence, g-C3N4 can be considered as a potential candidate for methylene blue photodegradation.

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Effect of calcination temperature, pH and catalyst loading on photodegradation efficiency of urea derived graphitic carbon nitride towards methylene blue dye solution

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Effect of pH on adsorption and photocatalytic degradation efficiency of different catalysts on removal of methylene blue.

Polycyclic aromatic hydrocarbons (PAHs) represent a large class of persistent organic pollutants in an environment of special concern because they have carcinogenic and mutagenic activity. In this paper, we focus on and discuss the effect of different parameters, for instance, initial concentration of Anthracene, temperature, and light intensity, on the degradation rate. These parameters were adjusted at pH 6.8 in the presence of the semiconductor materials (TiO2) as photocatalysts over UV light. The main product of Anthracene photodegradation is 9,10-Anthraquinone which isidentified and compared with the standard compound by GC-MS. Our results indicate that the optimum conditions for the best rate of degradation are 25 ppm concentration of Anthracene, regulating the reaction vessel at 308.15 K and 2.5 mW/cm2 of light intensity at 175 mg/100 mL of titanium dioxide (P25).

/pdf/photocatalytic-degradation-of-anthracene-in-closed-system-2igk5z7cag.pdf

Photocatalytic Degradation of Anthracene in Closed System Reactor

There is an urgent need for the design and development of new and safer drugs for the treatment of HIV infection, active against the currently resistant viral strains. New derivatives of the non-steroidal anti-inflammatory drug indomethacin bearing benzimidazoles, benzothiazole, purine and pyridine residues 8 - 13 were synthesized with the aim of developing new non-nucleoside reverse transcriptase inhibitors (NNRTIs).Alternatively, new imine analogs 16 - 20 were synthesized from condensation of indomethacinyl hydrazide 15, prepared from the ester 14, with various ketone precursors. Treatment of 15 with phenyl isothiocyanate or triethyl orthoformate afforded the phenylcarbonothioyl and the oxadiazole derivatives 21 and 22, respectively. The new compounds were assayed against HIV-1 and HIV-2 in MT-4 cells. Compounds 9 and 10 were the most active in inhibiting HIV-2 and HIV-1, respectively, with EC50 ≥ 17.60 μgmL−1 and > 1.15 μgmL−1 (therapeutic indexes (SI) of ≥ 3 and < 1, respectively), and are leading candidates for further development. Graphical Abstract Synthesis and anti-HIV Activity of New Benzimidazole, Benzothiazole and Carbohyrazide Derivatives of the anti-Inflammatory Drug Indomethacin

Synthesis and anti-HIV Activity of New Benzimidazole, Benzothiazole and Carbohyrazide Derivatives of the anti-Inflammatory Drug Indomethacin

Background In continuation of our search for new anti-HIV and anti-HCV agents, the suggestion, synthesis and structure elucidation of a new series of 2,6-diamino-4-alkylthio- or (2-benzylhydrazinyl)-5-p-chlorophenylazopyrimidines), 2,6-diamino-4-(2-benzylhydrazinyl)-5-(aryl-[1,1'-biphenyl]-4-yl)pyrimidines, 2,6-diamino-4-(aryl)-5-(aryl[1,1'-biphenyl]-4-yl) pyrimidines), 6-(aryl)-1,3-dimethyl-5-nitro pyrimidine-2,4-dione and 6-amino-4-methoxy-N,N-dimethyl-6-arylpyrimidines were described. Methods The anti-HIV-1 (strain IIIB) and HIV-2 (strain ROD) activity of the newly synthesized pyrimidine analogues was evaluated in vitro in human MT-4 cells using the MT-4/MTT assay. Similarly, the same compounds were evaluated in vitro for their selective antiviral activity against HCV in the Huh 5-2 replicon system (type 1b, Con1 strain). Results None of the tested compounds exhibited inhibition of HIV-1 and HIV-2 replication in cell culture. Even though many compounds yielded a 50% effective concentration in the HCV replicon system with selectivity indexes up to 6.9, none of the compounds matched the selection criteria of a selective inhibitor of virus replication in this assay (that is, >70% inhibition at concentrations that do not elicit an anti-metabolic effect on the host cells). Conclusions Structural modification of these compounds might optimize their anti-HCV activity by introducing diverse and potent functional groups at the pyrimidine backbone, like nitrile residue. Because of the nature of the molecules, these new derivatives will also be evaluated for their potential anti-HIV activity.

https://journals.sagepub.com/doi/pdf/10.3851/IMP2400

Exploration of the in vitro antiviral activity of a series of new pyrimidine analogues on the replication of HIV and HCV.

/pdf/determination-of-benzo-a-pyrene-in-surface-water-of-shatt-al-2f8h0xc616.pdf

Sadiq J. Baqir

Papers

Effect of pH on adsorption and photocatalytic degradation efficiency of different catalysts on removal of methylene blue.

Photocatalytic Degradation of Anthracene in Closed System Reactor

Synthesis and anti-HIV Activity of New Benzimidazole, Benzothiazole and Carbohyrazide Derivatives of the anti-Inflammatory Drug Indomethacin

Exploration of the in vitro antiviral activity of a series of new pyrimidine analogues on the replication of HIV and HCV.

Determination of Benzo(a)pyrene in Surface Water of Shatt Al-Hilla River, Iraq