A Strategy for Complete Degradation of Metformin Using Vortex-Based Hydrodynamic Cavitation

Abstract

The present work successfully establishes the degradation of metformin, an antidiabetic drug, using vortex flow-based hydrodynamic cavitation (HC) and process intensification. Studies were carried out on a pilot plant (1 m 3 /h) and for high initial concentrations, 10−20 mg/L. Effects of intensifications using aeration and the addition of hydrogen peroxide on various process parameters were evaluated. A low degradation (3−5%) by HC at ΔP of 1 bar could be improved by process intensification using hydrogen peroxide (33%). Importantly, a very high 95% metformin degradation was obtained at pH 4 with excellent cavitational yields up to 162 × 10 −5 mg/J, further extending to 100% the degradation using HC+H 2 O 2 , an order of magnitude enhancement of 900%. The synergy can be drastically enhanced by process modifications. Per pass degradation enhancement was huge, 100 times, corresponding to an order of magnitude cost reduction compared to conventional hydrodynamic cavitation. The established strategy can have positive implications for industrial wastewater treatment.

Hydrodynamic Cavitation and Advanced Oxidation for Enhanced Degradation of Persistent Organic Pollutants: A Review

“…The utilization of cavitation as a pre-treatment method is highly advantageous owing to its cost-effectiveness, absence of supplementary chemical usage, and absence of additional waste generation, as reported in previous studies [8]. Cavitation has demonstrated the effective degradation of various compounds, including phenol, dimethylformamide, magenta dye, 2-chlorophenol, methylene blue, triclosan, rhodamine B, octanol, cyclohexanol, and naproxen [17,18]. HC is deemed to possess superior energy efficiency and is frequently deemed appropriate for commercial-scale implementation and expansion.…”

“…The venturi configuration is frequently utilized in processes characterized by lower intensity, typically requiring pressures ranging from 15 to 20 bar [44,45], and involving physical transformations. In contrast, the utilization of the orifice flow configuration is commonly observed in the context of more intense chemical reactions [17,46]. However, a research investigation in the field of disinfection against pathogenic microorganisms has demonstrated that venturi-type reactors demonstrate enhanced efficacy in comparison to orifice plates [47].…”

“…Research findings suggest that an ideal range of inlet pressure between 4 to 10 bars results in enhanced biodegradability [17]. The impact of pressure variation on the treatment of distillery wastewater was investigated.…”

“…The effectiveness of an HC reactor or process is contingent upon several subprocesses, including the positioning, generation rate, and paths of cavities. These factors are influenced by the design of the flow rate, cavitation reactor, dissolved gases, pressure, temperature, and other relevant parameters [17]. The collapse of cavities and the resulting physicochemical effects occur when cavities are formed and transported by a flowing fluid [30,74].…”

“…Several studies have conducted comprehensive cost analyses and comparisons, which indicate that cavitation can serve as a viable alternative to other oxidation processes [20]. When considering the comparison between cavitation and biological oxidation, it is important to acknowledge the existence of a tradeoff between the cost of the process and the efficiency of the treatment, as indicated in Table 6 [17]. For instance, the financial expenditure associated with biological treatment is significantly lower than that of cavitation [52].…”