Destruction of endocrine disruptor compounds (EDCs) with ozone process

Abstract

Resorcinol is a serious concern in our water system as it is present in most of our household products such as fabrics, personal care products and electrical devices. (Primozone, 2017) Resorcinol is categorised as an endocrine disruptor because it can disrupt the human metabolism, triiodothyronine (T3) and thyroxine (T4), interfering with our thyroid activity. This will result in health risks for human and for the aquatic species in the water bodies. (C. Groshart, P.C. Okkermann, 2000) There is an urgent need to find the most effective way to destroy resorcinol and prevent it from being discharged into water bodies, or coming back into our water supply. Several efforts have been directed towards eliminating resorcinol using advanced oxidation processes, irradiation and ozone oxidation process. In this project, ozone oxidation process is employed to degrade resorcinol and its effectiveness is evaluated using high performance liquid chromatography (HPLC) for degradation analysis and total organic carbon (TOC) for mineralisation analysis. The effect of resorcinol concentrations, ozone flow rates, and pH values are investigated. It is observed that full degradation is achieved up to 7 mg/L of initial resorcinol concentration, beyond which the degradation decreases with increasing initial resorcinol concentration. In order to further assess the effectiveness of higher ozone flowrates, 15 mg/L of initial resorcinol is chosen to study the effect of ozone concentration. Like degradation, the degree of mineralisation also decreases with increasing initial resorcinol concentration, up to 20 minutes, beyond which a plateau is reached. When more ozone is available for reaction, there are more interaction with resorcinol compound, thus degradation occurs at a faster rate. As pH increases, there was an increase in degradation of resorcinol, with a most effective pH value at pH 8. At pH 8, resorcinol is completely removed at reaction time of 10 minutes, and mineralisation occurs at 25.1%. Thus, the most optimal condition for the most effective degradation and mineralisation of resorcinol is given at initial resorcinol concentration of 15 mg/L, with 400mg/h of ozone flow rate, at pH 8.