Zinc (II) ion recovery by biosorption onto powdered waste sludge (PWS): effects of operating conditions

Abstract

Powdered waste sludge (PWS) obtained from a paint industry wastewater treatment plant and pretreated with 1% H 2 O 2 was used for biosorption of Zn(II) ions from aqueous solution. The effects of operating conditions, pH, temperature, agitation speed, PWS particle size, Zn ion and PWS concentrations on the extent of Zn ion biosorption were investigated in batch experiments. The optimum pH resulting in maximum Zn ion biosorption was found to be pH = 5, since Zn ions precipitated in the form of Zn(OH) 2 at pH levels above 5. The rate and extent of Zn ion biosorption increased with temperature between 25 and 50• C, although biosorption was not strongly sensitive to temperature variations since the activation energy was low at 4.5 kcal mol −1 . Biosorbent particle size had a significant effect on Zn ion biosorption, yielding high percentage Zn removals at small particle sizes (D p < 100 µm) or large surface areas of PWS. Agitation speed also considerably affected the extent of Zn ion removal, and should be above 150 rpm in order to obtain a high rate. The extent of Zn ion biosorption was also affected by the initial Zn ion and PWS concentrations. At constant biosorbent (PWS) concentration, percentage Zn ion removal decreased, but the biosorbed Zn concentration increased with increasing initial Zn ion concentrations. However, at constant initial Zn concentrations, percentage Zn removal increased, but the biosorbed Zn ion concentration decreased with increasing adsorbent (PWS) concentration. With a maximum Zn ion biosorption capacity of 168 mg g −1 powdered waste sludge was proven to be an effective biosorbent compared to other biosorbents.

Removal of mercury(II) from aqueous solution using moss (Drepanocladus revolvens) biomass: Equilibrium, thermodynamic and kinetic studies

“…Contact time is one of the most important parameters for successful usage of the biosorbents in practical and rapid sorption application [35,36]. Fig.…”

Characterization and adsorption mechanism of Zn2+ removal by PVA/EDTA resin in polluted water

“…This method has been reportedly used in many studies for analysis of Zn(II) [25][26][27]. The concentration of Zn(II) ions in the effluent was determined spectrophotometrically by developing a blue color with zincon in basic solution as a complexing agent [28].…”

Effective removal of zinc ions from aqueous solutions using crab carapace biosorbent

“…A number of studies have evaluated the application of biosorption for the removal of Zn 2+ . These include the use of natural materials such as moss [8], peat [9,10], zeolite and bentonite [11], tree leaves [12], mixed mineral [13,14]; microbial and algal biomass [4,15] including seaweed, yeast, fungi, bacteria; industrial and agricultural wastes [7,[16][17][18][19][20] such as peanut hulls, corncobs, cornstarch, hazelnut shells, waste tea leaves, blast furnace slag, sea nodule residue, sugar beet pulp, lignite, lignin and powdered waste sludge, etc. Despite the relative simplicity and potential cost-effectiveness of biosorption, metal removal using low-cost biosorbents is relatively unproven and needs further development before it may be applied routinely in practice and thus considered an alternative to use of ion-exchange resins or activated carbons.…”