Humic substance-enhanced ultrafiltration for removal of cobalt

Removal of heavy metal ions from wastewaters: A review

“…The main concern of the previous PEUF studies was to find suitable polymers to achieve complexation with metal ions. Complexing agents such as polyacrylic acid (PAA) (Labanda et al, 2009), polyethyleneimine (PEI) (Aroua et al, 2007;Molinari et al, 2008), diethylaminoethyl cellulose (Trivunac and Stevanovic, 2006) and humic acid (Kim et al, 2005), etc., have been proven to achieve selective separation and recovery of heavy metals with low energy requirements.…”

Buffer capacity of humic acid: Thermodynamic approach

“…The external water was replaced during the first 5 h and then every 12 h until chloride could not be detected [5,6].…”

“…Total acidity and carboxylic acid fraction of humic acid samples were determined by potentiometric titration, with some modification of the original procedure [5]. Isoelectronic point (IEP) was followed by potentiometric titration of humic acid, which was carried out by using 50.0 mL of aqueous suspension of HA 40.0 g/L.…”

“…Humic acid controls several physical and chemical properties of soil such as aggregate stability, sorption and transport of hydrophobic organic compounds, bioavailability, and complexation of metals in ecosystems due to their high content of acidic functional groups [5,6]. Moreover, the acid groups and proton-binding abilities of HA directly affect the acid-base buffering capacity of soils [7].…”

Influence of phosphate ions on buffer capacity of soil humic acids

“…They influence several processes such as sorption and transport of hydrophobic organic compounds, stabilization of aggregates and bioavailability and complexation of metal cations (Khaled and Fawy, 2011;Kim et al, 2005). Among many methods for obtaining information about physico-chemical properties of HAs (and organic soils in general), potentiometric titration is frequently used.…”