حذف سورفاكتانت آنيوني سديم دودسيل سولفات از فاضلاب با فرايند اكسيداسيون پيشرفته UV/H2O2

The Removal of Sodium Dodecyl Sulphate Anionic Surfactant from Wastewater Using UV/H2O2 Advanced Oxidation Process

فاضلاب صنايع مختلف و همچنين فاضلاب شهري حاوي مقادير مختلفي از انواع سورفاكتانت‌ها است. سورفاكتانت‌ها به‌خاطر داشتن خصوصيات فيزيكي و شيميايي خاص و همچنين پايين بودن تجزيه‌پذيري بيولوژيكي در دسته مواد مقاوم به تصفيه‌ي بيولوژيكي قرار مي‌گيرند. روش‌هاي مرسوم و در دسترس، ناتوان از حذف كامل سورفاكتانت‌ها است. فرايند اكسيداسيون پيشرفته قادر به حذف دسته‌هاي گوناگون سورفاكتانت‌ها است. در اين پژوهش، حذف سورفاكتانت با فرايند اكسيداسيون پيشرفته بررسي شده است. اين مطالعه در مقياس آزمايشگاهي به صورت ناپيوسته با استفاده از يك رآكتورUV با حجم 80 ميلي‌ليتر براي ارزيابي كارايي فرايند اكسيداسيون پيشرفته براي حذف سورفاكتانت از فاضلاب مصنوعي انجام شد. در اين آزمايش اثر شاخص‌هاي مختلف مثل زمان و غلظت‌هاي اوليه سورفاكتانت بررسي شد. براي كاوش سورفاكتانت از روش آكريدين ارنج استفاده شد. اين مطالعه نشان داد كه فرايند اكسيداسيون پيشرفته UV/H2O2 نسبت به دو روش ديگر، بازده حذف بالاتري براي سورفاكتانت آنيوني SDS دارد. در فرايند UV/H2O2 در 8pH=، با غلظت سورفاكتانت mg/L700، زمان تماس 30 دقيقه و مقدار پراكسيد هيدروژن 5/0 ميلي‌مول، بازده حذف، 92 درصد به‌دست آمد. همچنين مشاهده شد كه با افزايش غلظت سورفاكتانت، بازده حذف كاهش مي‌يابد. نتايج به‌دست‌آمده نشان داد كه فرايند اكسيداسيون پيشرفته UV/H2O2 براي حذف سورفاكتانت از فاضلاب، بازده بالايي دارد.

Surfactants are used to aid in cleaning equipment and surfaces by restaurants, dairy farms, and food processing plants and are among the basic constituents of organic pollutants in domestic as well as industrial wastewaters causing great environmental damages. Due to their high volume use, surfactant chemicals have the potential for broadscale release into aquatic and terrestrial environment. Surfactants can reach humans, animals and plants from the ground waters used as drinking water supplies. Besides the toxic effects of surfactants their existence in waters even under the toxic level causes many adverse effects on biological life. They cause pathological, physiological and biochemical effects on aquatic animals. A large number of surfactants, including the anionic types employed in the present study, have relatively low biodegradability. Due primarily to economic reasons, it is impractical to replace those low biodegradable surfactants in all household and industrial applications. In the past decades, ozonation and other advanced chemical oxidation has been suggested and investigated by many researchers for pretreatment of refractory surfactants. These investigators have found that the biodegradability of the refractory surfactants can be considerably enhanced by ozonation or photocatalytic treatment. Although effective in improving the biodegradability of refractory surfactants, strong oxidation by ozonation or photocatalytic treatment is a relatively costly method. An alternative advanced oxidation method which is as efficient and yet less expensive to implement would be highly desirable. A method meeting these requirements and deserving attention is the UV/H2O2 oxidation process. This method employs hydrogen peroxide (H2O2) and UV to form a strong oxidizing agent (hydroxyl radicals) during the oxidation process. Hydroxyl radicals have been known to possess a stronger oxidation potential than ozone, 2.8 V for OH and 2.07 V for ozone. This study carried out at a bench scale unit consisted of a batch UV reactor with a working volume of 80 ml to evaluate efficiency of UV/H2O2 AOP in the degradation of surfactant from synthetic wastewater.The effects of various parameters including reaction time, H2O2 concentration was investigated. The concentration of model surfactant was determined by the acridin orange method.The present study showed that the UV/H2O2 AOP have higher efficiency than singl UV and H2O2 processes for sodium dodecyl sulphate( SDS) anionic surfactant removal. In this process for the solution with a surfactant concentration of 700mg/L and H2O2 conentration of 0.5mMol, the removal efficiency of 92% was achieved with a reaction time of 30 minute. Also the degradation efficiency was found to be decreased by releasing in surfactant concentration. UV/H2O2 advanced oxidation process is capable of degrading the SDS surfactant from wastewater by high efficiency. Keywords: Wastewater, Surfactant, Sodium dodecyl sulphate, Advanced oxidation process