Summary of Geography doctoral thesis: Study on denaturation of Laterite ores by La2O3 and CeO2 to treat arsenic and phosphate in water

Synthesization and structural characterization of nano La2O3, nano CeO2, nano La2O3- CeO2 on laterite by sol - gel combustion method using gelatin precursor; investigation the adsorption and desorption capacity of arsenic, phosphate on La2O3 nanomaterials, CeO2 nanomaterial, mixed oxides La2O3-CeO2 nanomaterial and La2O3-CeO2 nanomaterials on laterite.
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Summary of Geography doctoral thesis: Study on denaturation of Laterite ores by La2O3 and CeO2 to treat arsenic and phosphate in water MINISTRY OF EDUCATION VIETNAM ACADEMY OF AND TRAINING SCIENCE AND TECHNOLOGY GRADUATE UNIVERSITY OF SCIENCE AND TECHNOLOGY DAO HONG DUC STUDY ON DENATURATION OF LATERITE ORES BY LA2O3 AND CEO2 TO TREAT ARSENIC AND PHOSPHATE IN WATER Major: Enviromental engineering Major code: 92 5. 03.20 SUMMARY OF GEOGRAPHY DOCTORAL THESIS Ha Noi - 2020 The thesis was completed in: Inorganic material room, Institute of materials science, Vietnam Academy of Science and Technology Science instructor 1: Assoc. Prof. PhD. Do Quang Trung Science instructor 2: Assoc. Prof. PhD. Dao Ngoc Nhiem Reviewer 1: Reviewer 2: Reviewer 3: The thesis will be defended at the university's doctoral thesis evaluation council, meeting in the Graduate University of Science and Technology, Vietnam Academy of Science and Technology at …… hour ……, date …… month …… year 2020. - Thesis can be found in: - The Library of Graduate University of Science and Technology - Vietnam’s National Library Introduction 1. The urgency of the thesis Water potable resources contamination significantly affects on human health, especially underground water, one of the main water sources for Vietnamese people. To our knowledge, groundwater can be polluted by various contaminants like arsenic, ammonium, fluorine, nitrate, and phosphate... Regarding to arsenic pollution in groundwater in Vietnam, it has been studied by many national and international scientists. The results showed that there are many provinces and cities across the country with arsenic concentrations in excess of the regulation standards such as Hanoi, Vinh Phuc, Ha Nam... However, phosphate contamination and its accumulation in groundwater over time have not been much investigated in Vietnam. It is necessary to understand the presence of phosphate in water because it affects the quality of water sources and as much to human health. The sources for phosphate presence in groundwater can be explained by human activities such as using chemical fertilizers in agriculture, domestic wastewater, leachates, and livestock waste water... Up to date, to remove arsenic and phosphate in water, there are many methods such as: co-precipitation method, adsorption method, ion exchange method, and membrane method. In particular, the adsorption method is currently widely used because of its effectively high treatment efficiency, environmentally friendly methods, diverse precusor sources. The use of natural materials or the use of high-valence metals such as iron oxide, aluminum oxide, magnesium oxide resulted in good potentail phosphate removal. However, many researchers agreed that the oxides of rare earth elements have many more advantages. Some of them are widely applied in practice, especially for environmental treatment such as lanthanum, cerium in nano size. On one hand, the nano lanthanum oxides and nano cerium oxides have good ability to handle arsenic and phosphate. On the other hand, it is still quietly expensive in compare with other materials. Therefore, lanthanum oxide nanoparticles, cerium oxide are often deposited on laterite carriers for better economic efficiency. Laterite has many advantages compared to other materials in nature such as abundant reserves, simple mining and activation process, capable of handling high concentration of arsenic and phosphate. Therefore, the use of nano lanthanum oxide and cerium oxide nano as a material to treat arsenic and phosphate pollution in water was conducted in the thesis Study on denaturation of Laterite ores by La2O3 and CeO2 to treat arsenic and phosphate in water”. The thesis was completed with the main following contents. 2. The main content of the thesis Synthesization and structural characterization of nano La2O3, nano CeO2, nano La2O3- CeO2 on laterite by sol - gel combustion method using gelatin precursor. Investigation the adsorption and desorption capacity of arsenic, phosphate on La2O3 nanomaterials, CeO2 nanomaterial, mixed oxides La2O3-CeO2 nanomaterial and La2O3-CeO2 nanomaterials on laterite. Testing the ability to handle arsenic and phosphate in groundwater samples at Phu Ly, Ha Nam with La2O3-CeO2 / laterite nanomaterials with the experimental model. New contributions of the thesis 1 Successfully synthesized 4 types of nano materials La2O3, nano CeO2, La2O3-CeO2 nano-mixed materials and modified La2O3-CeO2 nanomaterials on laterite by sol-gel combustion method using gelatin. Fully investigated the arsenic and phosphate adsorption capacity in water of the four types of nano materials La2O3, nano CeO2, La2O3-CeO2 nanomaterials and La2O3-CeO2 nanomaterials on laterite . 3. The layout of the thesis. The thesis consists of 95 pages with 25 tables, 49 figures and 98 references. The thesis is composed of a 2-page introduction, an overview of 28 pages, experimental and methodology of 12 pages, results and discussion of 54 pages and conclusions of 2 pages. CONTENTS OF THE THESIS Chapter 1. Literature review On the basis of document analysis, this chapter summarized arsenic and phosphate pollution in groundwater, the harmful effects of arsenic and phosphate pollution on human health. Especially, this chapeter provided the evident of the increasing phosphate concentration in underground water. The process of removing arsenic and phosphate has many methods such as co-precipitation method, ion exchange method, adsorption method. To treat arsenic in water thoroughly, it is possi ...