Bibliometric analysis and literature review of ultrasound-assisted degradation of organic pollutants

Ultrasound as a clean, efficient, and cheap technique gains special attention in wastewater treatment. Ultrasound alone or coupled with hybrid processes have been widely studied for the treatment of pollutants in wastewater. Thus, it is essential to conduct a review about the research development and trends on this emerging technique. This work pre-sents a bibliometric analysis of the topic associated with multiple tools such as Bibliometrix package, CiteSpace, and VOSviewer. The literature sources from 2000 to 2021 were collected from Web of Science database, and the data of 1781 documents were selected for bibliometric analysis in respect to publication trends, subject categories, journals, authors, institutions, as well as countries. Detailed analysis of keywords in respect to co-occurrence network, keyword clusters, and citation bursts was conducted to reveal the research hotspot and future directions. The development of the topic can be divided into three stages, and the rapid development begins from 2014. The leading subject category is Chemistry Multidisciplinary, followed by Environmental Sciences, Engineering Chemical, Engineering Environmental, Chemistry Physical, and Acoustics, and there exists difference in the publications of different catego-ries. Ultrasonics Sonochemistry is the most productive journal (14.75 %). China is the leading country (30.26 %), followed by Iran (15.67 %) and India (12.35 %). The top 3 authors are Parag Gogate, Oualid Hamdaoui, and Masoud Salavati-Niasari. There exists close cooperation between countries and researchers. Analysis of highly cited papers and keywords gives a better understanding of the topic. Ultrasound can be employed to assist various processes such as Fenton-like process, electrochemical process, and photocatalysis for degradation of emerging organic pollutants for wastewater treatment. Research topics in this field evolve from typical studies on ultrasonic assisted degradation to latest studies on hybrid processes including photocatalysis for pollutants degradation. Additionally, ultrasound -assisted synthesis of nanocomposite photocatalysts receives increasing attention. The potential research directions in-clude sonochemistry in pollutant removal, hydrodynamic cavitation, ultrasound-assisted Fenton or persulfate pro-cesses, electrochemical oxidation, and photocatalytic process.

Automated summary

Ultrasound is a promising technique for wastewater treatment, as it is clean, efficient, and affordable. This review paper analyzes the research development and trends of ultrasound in wastewater treatment through bibliometric analysis. The study reveals the publication trends, subject categories, journals, authors, institutions, and countries associated with ultrasound in wastewater treatment. The analysis highlights the research hotspots, cooperation between countries and researchers, and potential future directions in the field.