Evaluation of sterilization possibility in water environment of activated nano mno2 coated on

Evaluation of sterilization possibility in water

environment of activated nano MnO2 coated on

calcined laterite

Cao Việt

Trường Đại học Khoa học Tự nhiên

Luận văn ThS Chuyên ngành: Quản lý chất thải và xử lý vùng ô nhiễm

Người hướng dẫn: PGS.TS Trần Hồng Côn

Năm bảo vệ: 2011

Abstract: The TEM images of solution clearly reveal the presence of a large

quantity of nanomanganese dioxide particles with lozenge shape and barked

sphere with diameters around 30nm. The SEM images of material’s surface

shows the distribution of barked sphere shape nano MnO2 all over laterite

surface.

- Investigation sterilizing possibilities in static condition and dynamic condition.

- Manganese has affect in sterilizing capabilities of BRM. It reacts with MnO2

to create semi-product [MnO2.Mn].nO2 which plays as strong sterilization

substances.

Keywords: Quản lý chất thải; Xử lý ô nhiễm; Hóa học môi trường

Content

1. Introduction

1.1 Water situation in general

Water is one of the world’s most essential demands for human life, and the

origin of all animal and plant life on the planet. Civilization would be impossible

without steady supply of fresh and pure water and it has been considered a

plentiful natural resource because the sensitive hydrosphere covers about 75% of

the Earth's surface. Its total water content is distributed among the main

components of the atmosphere, the biosphere, oceans and continents. However,

97% of the Earth's water is salty ocean water, which is unusable for most human

activities. Much of the remaining 3% of the total global water resource, which is

fresh-water, is locked away in glaciers and icebergs. Approximately 20% of the

freshwater resources are found as groundwater, and only 1% is thought to be

easily accessible surface water located in biomass, rivers, lakes, soil moisture,

and distributed in the atmosphere as water vapor. [1]

In the process of rapid development of science and technology, the demand for

pure water is increasing to serve multifarious purposes in different types of

industries. Global water consumption raised six folds in the past century, double

the rate of population growth. In addition, the boom in world’s population during

recent decades, has contributed to the dramatically rising demand of pure water

usage for both household and industrial purposes. The high population density

and industrialization speed have triggered the hydrosphere to be polluted with

inorganic and organic matters at a considerable rate. Moreover, to satisfy the

food demand, a number of harmful chemicals such as pesticides and herbicides

are used in order to improve the productivity in agricultural production, which

also causes the scarcity of clean resources. [1]

1.2 Water sterilization

Water sterilization technology is useful in various ways for our daily life. For

example, it is used in water and sewerage systems treatment. Methods commonly

used for sterilization include chemicals, heat, ultraviolet (UV) radiation, and

ozone. Chemicals (chlorine, peroxide, etc.) are utilized extensively for

sterilization because of their simplicity; however, they probably form unexpected

effects, such as modifying the quality of the target. In addition, sterilization by

chlorine usually generates odorous substances and bio-hazardous materials. [2]