Article info.

ABSTRACT

Received date: 22/08/2015

Accepted date: 30/11/2016

Biomass of digested sludge and resting sludge can be easily applied as a cheap bio-adsorbent for heavy metal ions such as Pb²⁺, Cu²⁺ and Cd²⁺. Langmuir model was found to fit the experimental adsorption and desorption data of the heavy metal onto the biomass of sludge. There was competition uptake between the difference metal with another when the adsorption system has the di-metal, and tri-metal combination. The maximal adsorption capacity of resting sludge was 0.517 mM Pb²⁺/g; 0.552 mM Cu²⁺/g; 0.389 mM Cd²⁺/g, and the maximal adsorption capacity of the digested sludge was 0.478 mM Pb²⁺/g, 0.43 mM Cu²⁺/g and 0.549 mM Cd^2+/g. In the absorption system, it was found that, di-metal combine such as (Cu²⁺ - Cd²⁺), (Pb²⁺ ­ Cd²⁺), and (Cu²⁺ - Pb²⁺), the metal uptake Cu²⁺ ≈ 3Cd²⁺, Pb²⁺ > 3Cd²⁺, and Cu²⁺ ≈ Pb²⁺ respectively. When tri-metal Cu²⁺ - Cd²⁺ - Pb²⁺ combines the number of complex formation varies in the following order: Pb²⁺ > Cu²⁺ > Cd²⁺. Extracellular polymeric substances (EPS) were extracted by sonication method. Humic substances were greater than protein and polysaccharide for digested sludge, for resting sludge the protein is greater than humic. The highest ratio protein/polysaccharide varied from 1.25 to 2.7 for resting sludge. Affinity absorption of Cu²⁺ and Pb²⁺ was higher than Cd²⁺, which have the competition metal uptake with functional groups such as hydroxyl, carbonyl, amide on the biomass surface of the sludge.

Keywords

Activated sludge, Bio-sorption, Cd²⁺, Cu²⁺, Pb²⁺

Cited as: Trung, N.D., Phuong, T.D. and Ping, N., 2016. Sorption of Pb(ii), Cu(ii) and Cd(ii) by biomass of the different activated sludge. Can Tho University Journal of Science. Vol 4: 20-27.