Use of novel composite coagulants for arsenic removal from waters : experimental insight for the application of polyferric sulfate (PFS)

In the present study, several pre-polymerized coagulants of iron and aluminum were tested for their efficiency towards As(V) and As(III) removal from water sources. The results showed that the pre-polymerized coagulants of iron, such as poly-ferric sulfate and poly-ferric silicate chloride, were very efficient for As(V) removal. With regard to As(III) removal, among all examined coagulants, including the conventional ferric chloride, only the poly-ferric sulfate (PFS) was able to reduce As(III) to concentrations below the drinking water regulation limit of 10 μg/L. In contrast, all tested composite coagulants based on aluminum were not capable of removing efficiently both species of arsenic. PFS addition in water containing 4 mM of alkalinity and 25 μg/L of As(V) and As(III) (i.e., total arsenic concentration 50 μg/L) resulted in finished water with less than 5 μg/L arsenic, only by dosing 5 mg Fe-PFS/L at pH 7, whereas, simultaneously, the residual iron concentration was found well below its drinking water regulation limit of 200 μg/L. The use of PFS could provide a viable alternative for As(III) and As(V) removal at household treatment level for application in vulnerable communities, without the need of any additional treatment, such as oxidation of As(III) to As(V).

Subjects

arsenic removal

composite inorganic coagulants

poly-ferric-sulfate

alkalinity

DDC Class

620: Ingenieurwissenschaften

Lizenz

https://creativecommons.org/licenses/by/4.0/

Name

sustainability-09-00590-v2.pdf

Size

963.73 KB

Format

Adobe PDF

Options

Use of novel composite coagulants for arsenic removal from waters : experimental insight for the application of polyferric sulfate (PFS)