Options
Green iron-based composite materials for arsenic remediation
Author
Lee, Yen Wei
Supervisor
Wong, Ka Lun
Tan, Swee Ngin
Abstract
Arsenic is present in groundwater due to natural and anthropogenic activities. Many developing and developed countries groundwater’s arsenic concentration exceeds the guideline set by the World Health Organisation (WHO) and United States Environmental Protection Agency (USEPA) of 10 parts per billion (ppb) for safe drinking water. Ingestion of arsenic tainted waters can lead to serious health problems such as skin cancer and cardiovascular diseases. There are various methods for removal of arsenic in water, varying from the complicated and expensive (e.g. reverse osmosis) to simple and accessible (e.g. coagulation and flocculation) methods. This study aims to characterise the efficiency of an iron based sorbent in removing arsenic from water, a method that is simple and readily accessible. Parameters such as pH and concentration of arsenic of the water samples, volume of water samples and agitation during sorption process were investigated.
The results showed that a higher percentage of arsenic remediation was achieved under acidic conditions (pH 3 and pH 5.5) and the amount of arsenic left in remediated water samples were reduced to below 10 ppb. At pH 5.5, the extent of iron leaching was lower and conformed to the secondary standard level of 0.3 ppm recommended by USEPA for iron present in drinking water. Other parameters such as volume of water samples and agitation during sorption process did not significantly affect arsenic removal in acidic conditions. Complete arsenic removal was quickly obtained with 97% removal efficiency within the first 15 minutes and 1 hour for pH 3 and pH 5.5 respectively.
The sorption process correlates to a pseudo 2nd order model of chemisorption under acidic conditions (pH 3 and pH 5.5).
The results showed that a higher percentage of arsenic remediation was achieved under acidic conditions (pH 3 and pH 5.5) and the amount of arsenic left in remediated water samples were reduced to below 10 ppb. At pH 5.5, the extent of iron leaching was lower and conformed to the secondary standard level of 0.3 ppm recommended by USEPA for iron present in drinking water. Other parameters such as volume of water samples and agitation during sorption process did not significantly affect arsenic removal in acidic conditions. Complete arsenic removal was quickly obtained with 97% removal efficiency within the first 15 minutes and 1 hour for pH 3 and pH 5.5 respectively.
The sorption process correlates to a pseudo 2nd order model of chemisorption under acidic conditions (pH 3 and pH 5.5).
Date Issued
2015
Call Number
TD427.A77 Lee
Date Submitted
2015