Reduction of Nitrate by Nanosized Fe0 and Cu/Fe Bimetallic Particles
Date Issued
2005
Date
2005
Author(s)
Weng, Shih - Chi
DOI
zh-TW
Abstract
Nitrate is a common pollutant in the environment and pose potential health risk to cause cancer. Current technologies such as ion exchanges and reverses osmosis do not destroy and generate secondary brine wastes. Biological denitrification is unfavorable because of it requires intensive maintenance and high cost. Our research focuses on chemical reduction technology, and finds a more powerful and economic process to deal with nitrate pollution. Zero-valent iron (Fe0) is the most widely used material in the previous researches of the chemical reduction technology. Fe0 transforms nitrate to ammonia in a great amount, and decreases the health risk of nitrate to nitrite.
In our experiment, we use a strong reductant (NaBH4) to produce high active nano-Fe0 which has a small diameter within the range of only 1~103nm, and yet a large surface area of 56.6m2/g. In comparison with commercial iron powder, the reduction capacity of nano-Fe0 is considered relatively large.
In fact, there are many kinds of negative ion other than nitrate in real groundwater. We use batch test to find the reaction of nano-Fe0 with nitrate when negative ions presents. There are six common ions is discussed：Fluoride, chloride, bromide, carbonate, sulfate, and phosphate. We also control reaction temperature from 10℃ to 60℃ to see how the reaction rate changes in response. In other hand, we synthesize nano-Cu/Fe bimetallic particle to enhance the capability of reducing pollutants, and test in all situations the same with nano-Fe0.
According to the experimental results, there are great effects to reducing nitrate by controlling temperature. The reaction rate raise with temperature increase. The presence of negative ions also causes the nitrate reaction rate slow down. The one-valent negative ions (Fluoride, Chloride, Bromide) interferes the nitrate reduction by increasing the rate of corroding iron surface and consuming the reactive site. The others negative ions (Carbonate, Sulfate, and Phosphate) restrain the reaction by forming complex compounds and precipitating on the particle. This phenomenon would cover the reactive site and block the contact of nitrate and iron surface.
Subjects
奈米
零價金屬鐵
雙金屬
硝酸根
nano
zero-valent iron
bimetal
nitrate
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-94-R92541117-1.pdf
Size
23.53 KB
Format
Adobe PDF
Checksum
(MD5):7a04183e203433f4c35b46b9d9220df2