A Study on the Removal of Chromium(VI) from Waste Solutions by Adsorption on to Sawdust in Stirred Vessels

Abstract

The ability of sawdust to adsorb chromium(VI) from waste solutions has been studied in a batch reactor under forced convection conditions. Variables investigated were the rotational speed of the impeller, the initial concentration of chromium(VI) in solution and the weight and particle diameter of the sawdust. Increasing both the rotational speed of the impeller and the initial concentration of chromium(VI) in solution led to an increase in the volumetric mass transfer coefficient (k) according to the relationships k ∝ ω)0.71 and k ∝ C0.26, where ω is the rotational speed of the impeller (rev./min) and C0 is the initial concentration of chromium(VI) in solution (mg/dm3). On the other hand, the volumetric mass transfer coefficient was found to decrease with increasing particle diameter of sawdust (dp) according to the relationship k ∝ dp−0.87. The removal of chromium(VI) was also found to be significantly dependent on the weight of sawdust. Analysis of the equilibrium isotherm data has been undertaken using the Freundlich and Langmuir equations. The maximum adsorption capacity of sawdust for chromium(VI) was found to be 4.44 mg/g.

Heavy metal adsorption onto agro-based waste materials: A review

“…The removal of heavy metal ions using low-cost abundantly available adsorbents: agricultural wastes such as tea waste and coffee [55], hazelnut shells [56][57][58], peanut hull [59,21], red fir [60] and maple [61] sawdusts [62,63], pinus bark [64][65][66][67] and different bark samples [68][69][70][71][72][73][74][75][76][77], palm kernel husk [78] and coconut husk [79,80], peanut skins [81], modified cellulosic materials [82,83], chemically modified cotton [84], corncobs [85] and modified corncob [86], rice hulls [87], apple wastes [88], coffee grounds [89], bark [90,91], modified bark [37], wool fibers [92], tea leaves [93], and wool, olive cake, pine needles, almond shells, cactus leaves, charcoal [94], modified lignin [48,95,96], banana and orange peels …”

Applications of Bio-waste Materials as Green Synthesis of Nanoparticles and Water Purification

“…Agricultural material such as banana and orange peels. [10] Bagasse pith, sawdust wastes [11], maize cob, coconut husk fibres [12], nut shells [13], soybeans and cotton seed hulls have been evaluated for their adsorptive properties. These materials have been reported to adsorb different pollutants such as heavy metal ions, dyestuff and other toxic pollutants [14], have been evaluated for the adsorption of heavy metal ions from wastewater.…”

Adsorption of Chromium(VI) from Aqueous Solutions by Coffee Polyphenol-Formaldehyde/Acetaldehyde Resins

“…A plot of / versus gives a linear relationship for the applicability of the second order kinetic model ( Figure 17). The adsorption capacity of coffee polyphenol resins compared to other materials is reported in the literature [31][32][33][34][35][36][37][38][39][40][41][42][43] and is given in Table 6. The sorption capacity of CFA and CAA resins are 175.44 and 143.32 mg/g, respectively, which are higher than adsorbents reported in the literature such as industrial as well as low-cost natural materials.…”