Effect of chemical modification of carboxyl groups in apple residues on metal ion binding

Spent Coffee Bioelastomeric Composite Foams for the Removal of Pb2+ and Hg2+ from Water

“…The maximum adsorption capacity is reached at about pH 5 where the surface is negatively charged. Nonetheless, at pH values exceeding 5, the adsorption capacity decreases, possibly due to Pb­(OH) 2 precipitate formation and therefore to the decrease of the number of ions present in water . This behavior is quite general and representative also for the other divalent heavy metal ions as also shown in the Supporting Information for Hg 2+ ions (Figure S4).…”

Modeling the effect of pH on biosorption of heavy metals by citrus peels

“…Since citrus peels are rich in pectin, it is only to be expected that carboxylate groups are one of the main functional groups in citrus peels. According to studies by Lee et al [10] and Reddad et al [7], phenolic functional groups could correspond to the higher pK a , while phosphate groups could be responsible for one of the intermediate pK a values. The site concentrations and pK a values listed in Table 1 are further validated by comparing the modeled charge (solid line) with experimental values (symbols) in Fig.…”

“…Very little information is available on biosorption performance of other pectin-rich materials, such as residues from fruit juice production, orange peels, apple residues, or other kinds of fruit peels [8][9][10][11][12][13], or pectin itself [14][15][16]. A recent review of low cost biosorbents highlighted the abundance of studies on seaweeds compare to fewer studies focusing on agricultural/food byproducts.…”

Application of apricot stone waste from fruit processing industry in environmental cleanup: copper biosorption study

“…Wastes such as grape stalk waste [14], banana and orange peels [15], apple residues [16], peach shells [17], grapefruit peel [18], pomegranate peel [19], citrus peels [20] previously were studied for the removal of metal ions.…”