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Water from the industries contains various organic effluents which are needed to be removed. Photocatalysis is an efficient method to degrade organic effluents that contaminate water and harmfully affect the environment. This study presents the structural, optical characteristics, and photocatalytic activity of the CuO/MoS2 and their composite with gCN. The hydrothermal approach was employed to fabricate MoS2 nanoflowers, and the co-precipitation method to fabricate CuO. The composite with gCN was prepared successfully using an ultrasonication approach. The physio-chemical properties of fabricated photocatalysts were investigated by various characterization techniques. SEM analysis revealed the nanoflower morphology of the prepared MoS2 sample. The photocatalytic activity was examined by the photodegradation of methyl orange dye and phenol. CuO/MoS2@gCN photocatalyst showed 85.14 % degradation of methyl orange and 63.50 % degradation of phenol. Also, the rate constant of CuO/MoS2@gCN was found to be 0.051 min−1 for MO dye and 0.02 min−1 for phenol, which is higher than other synthesized samples. The scavenging experiment was carried out to identify the most photoactive species involved in the organic pollutants photocatalytic degradation. Electrons served as the primary photoactive species in photocatalysis. Consequently, it is concluded from the results that CuO/MoS2@gCN could be employed as an efficient photocatalyst for wastewater treatment.

In this study, the phase transformations, crystallization kinetics and dissolution mechanism of β phase (Mg17Al12) in magnesium alloy AZ91 were investigated by optical microscopy, X-ray diffraction, differential scanning calorimetry and differential dilatometry. The results indicate that this AZ91 alloy undergoes a phase transformation during aging, a discontinuous precipitation of the β phase (Mg17Al12) at 150 °C at the grain boundaries and another continuous at 350 °C within the grains. The activation energy of the dissolution reaction of the β phase (Mg17Al12) under non-isothermal conditions is 116.781 kJ/mol, while it is 129.7383 kJ/mol under isothermal conditions. The Avrami coefficient, n, relevant for the dissolution kinetics of the β phase (Mg17Al12) is 1.152 and 1.211 in the non-isothermal and isothermal conditions respectively. The numerical coefficients m and Avrami n are 0.993 and 1.152.