نوع مقاله : پژوهشی
نویسندگان
1 دانشگاه بوعلی سینا، عضو هیئت علمی، دانشگاه تهران، عضو هیئت علمی وابسته
2 گروه عمران، دانشکئه فنی مهندسی، دانشگاه بوعلی سینا
3 گروه عمران، دانشکده مهندسی، دانشگاه بوعلی سینا
4 گروه عمران. دانشکده مهندسی. دانشگاه بوعلی سینا
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Increasing the efficiency of desorption of heavy metal contaminants from soil using enhancement agents is a focus of researchers. Enhancement agents increase the efficiency of decontaminating soil. However, limited attention has been given to the impact of surface potential, active functional groups, and soil retention phases on reducing the concentration of enhancement agents needed. This paper aims to determine the effect of a multi-stage washing process on the required concentration of enhancement agents for the removal of lead contaminants from kaolinite. In this study, lead-contaminated kaolinite and enhancement agents such as hydrochloric acid, acetic acid, and EDTA were used. The results show that with multi-stage washing, it is possible to achieve similar desorption percentages with lower concentrations of enhancement agents compared to conventional concentrations. Additionally, the enhancement agent EDTA is capable of desorbing contaminants at a much higher rate than acetic acid and hydrochloric acid in kaolinite containing 0%, 2%, and 9% carbonate. The use of the enhancement agent EDTA reduces the zeta potential of kaolinite. This behavior indicates the maintenance of the dispersed state of kaolinite even in acidic environments. Such a behavioral pattern in the chemical washing method preserves the dispersed structure and increases the contact surface of clay flakes with the enhancement agent. By increasing the interactive surface of clay with the electrolyte, more favorable conditions for enhancing the desorption rate are provided.
According to the results of this study, the use of the enhancement agent EDTA causes a significant amount of lead ions retained in the carbonate phase to transfer to the exchangeable phase, facilitating their removal from the soil. Based on the results of multi-stage washing, EDTA has shown very high efficiency in removing contaminants from kaolinite in all samples with varying carbonate percentages, even at low EDTA concentrations. This suitability aligns well with the results of FTIR tests, zeta potential measurements, and the role of EDTA in the contaminant-retaining phases.
کلیدواژه‌ها [English]
)