Correlation Analysis of the Experimental Data for In-Situ Chlorine Generation in Electrochlorination Process

Even though chlorination is a widely used disinfection technique, it has several disadvantages, such as formation of chlorates during prolonged storage, requirement for skilled supervision during operations, risk of leakage, and related accidents during transport and storage. Electrochlorination (EC) is one of the novel technologies generating in-situ chlorine, thereby limiting most of the disadvantages of conventional chlorination treatment for water disinfection. The correlation between the various influencing parameters for EC, which is important for achieving the optimal conditions for in-situ chlorine generation, is still unclear. The major objective of the present study is to provide a detailed correlation analysis between the parameters influencing the EC process based on the extensive experimental data generated from the developed lab-scale setup for electrochlorination using graphite electrodes and titanium electrodes separately. The present study also examined the rate of loss of the electrode materials to check the longevity of electrodes. The experimental results generated were used for comparative analysis of the EC process for maximum in-situ chlorine generation. A detailed principal component analysis (PCA) was performed for the data generated during experimentation to understand the correlation between the influencing parameters for optimum in-situ chlorine generation. The optimum conditions for maximum in-situ chlorine generation obtained from the experiments were 10 V electric voltage, 60 min electrolysis time, 4 cm distance between electrodes, and $3.5\mathrm{g}/\mathrm{L}$ electrolyte concentration, with maximum chlorine generation of $15.95\mathrm{mg}/\mathrm{L}$ obtained for titanium electrodes using NaCl electrolytes for the developed lab setup. The results of PCA established the correlation between the influencing parameters and concluded that the most significant parameter influencing chlorine generation was electrolyte concentration and electrochlorination time, and electric potential was moderately influential, whereas distance between electrodes was least influential. The rate of material loss was $15.3\mathrm{mg}/\min$ for titanium electrodes and $24\mathrm{mg}/\min$ for graphite electrodes, indicating titanium electrodes are more durable than graphite electrodes during a prolonged EC process. The applicability of the generated chlorine stock solution was also examined for drinking water sample disinfection and found to be effective.

Sustainable Development Goal 6 discusses the need for the provision of pathogen-free drinking water to each and every region of countries. Remote and rural areas that are deprived of disinfected drinking water can benefit from low-cost and easy maintenance of electrochlorination system. An electrochlorination system limits the disadvantages of conventional chlorination. The chlorine generated through an electrochlorination system was found effective in water disinfection. For optimized working of a electrochlorination unit, the influencing parameters for in-situ chlorine generation and their interdependence should be understood. The present study discusses the correlation between these influencing parameters for optimum in-situ chlorine generation during the electrochlorination process. The study will be helpful in understanding the optimum conditions for chlorine generation using the electrochlorination process for various electrodes and electrolyte combinations.