Semiconductor photocatalyst mediated advanced oxidation processes are regarded as one of the most efficient technologies to mitigate organic pollutants in water. However, poor activity under visible light and the recombination of photogenerated electron and hole pairs hinder large scale applicability of semiconductor photocatalysts for water purification. The modification of semiconductor photocatalysts with carbon quantum dots (CQDs) is of high importance due to low toxicity, aqueous stability, enhanced surface area, economic feasibility, good biocompatibility and chemical inertness of CQDs. In this review, we highlight strategies to improve the activity of conventional semiconductor photocatalysts via coupling with CQDs. The enhanced photocatalytic activity of CQD modified narrow and wide band gap photocatalysts is due mainly to up-conversion photoluminescence (UPCL) and the electron reservoir properties of CQDs, while in the case of Z-scheme photocatalysts CQDs act as an electron mediator. Finally, a conclusive outlook and suggested research directions are provided to address challenges such as the inadequate separation of photoinduced charge carriers.

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HighlightsRecent progress on magnetic iron oxides in photocatalytic water purification. Integration between non-magnetic and magnetic photocatalysts (MIOIPs).MIOP's synthesis and use for photocatalytic water purification.Quick magnetic separation and recyclability of MIOIPs.Scope and challenges associated with MIOIPs in water treatment.

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It has been established by physics education researchers that there is a correlation between the learner's behavior, their epistemological beliefs with which they come to the classrooms, and their success in a course. This study of Indian students and teachers explores expectations and beliefs in learning physics at the secondary and tertiary levels by making use of the Maryland Physics Expectation (MPEX) survey, which has been tested for both its validity and its reliability. The MPEX was administered to a sample of 265 Indian students at three different levels of study: (i) XII standard (high school), (ii) undergraduate (Bachelor of Science), and (iii) master's degree (Master of Science in Physics, MS). In India, a pre-post instruction difference between the attitudes of class XII, undergraduate, and master's students is observed with favorable improvement in master's students as compared to deterioration in both class XII and undergraduate students. A comparison of these results with those reported in similar studies conducted in four other countries (U.S., Turkey, Philippines, and Thailand) indicates that there is a difference between the U.S. students and those of the other three countries and also between U.S. experts and Indian teachers. In all countries (U.S., India, Turkey, Thailand, and Philippines) the basic trend of expectation from pre to post test remained the same-there was a deterioration observed in all levels of students. Indian MS students were an exception. A significant difference was observed in the expectations of U.S. experts and Indian teachers. The score of favorable views of Indian class XII and undergraduate students was observed to be less than U.S. students in many clusters. No significant difference was found between Indian male and female students' expectations at any level of study. This study shows that most Indian students have nowhere near an expert's expectations even after instruction, which might affect their motivation and success in physics courses and may have long-term implications on the quality of physics education in schools, colleges. and universities and the scientific research aspirations of the country.