Adsorption of Cr (VI) by treated weed Salvinia cucullata: kinetics and mechanism

Abstract

In the present study a new low cost, easily available and environmentally friendly adsorbent was used for removal of Cr (VI). The Cr (VI) removal efficiency of the adsorbent was studied as a function of contact time, pH, adsorbent dose, adsorbate concentration, temperature and stirring speed. Different adsorption model equations for kinetics, isotherm and rate mechanism of the process were used to find the best model, which fit well to the experimental data. A full factorial design of n k type was used to find a mathematical relation between the percentage of adsorption and variables affecting the adsorption process such as time, pH, adsorbate concentration and temperature. Using the Students 't' test, the significance of each term of the derived equation was tested. The insignificant terms were removed from the derived equation. The adequacy of the equation after removing the insignificant terms was tested using the Fisher adequacy test. From the factorial design analysis it is found that pH has the most pronounced effect followed by time, temperature and the adsorbate concentration. A column study was performed using the optimum operating conditions.

Efficacy of unmodified and chemically modified Swietenia mahagoni shells for the removal of hexavalent chromium from simulated wastewater

“…7c) as the initial Cr(VI) concentration increased from 20 to 100 mg/L. The increase in adsorption capacity of the adsorbents with an increase in initial Cr(VI) concentration was due to the higher probability of collision between Cr(VI) ions and adsorbents, and an increased driving force of the concentration gradient [53]. Thus, the Cr(VI) removal is dependent on the initial Cr(VI) concentration and contact time.…”

Utilization to Remove Pb (II) Ions from Aqueous Environments Using Waste Fish Bones by Ion Exchange

“…Generally, cost-effective alternative sorbents for heavy metal removal from water resources can be obtained from materials which exist abundantly in nature or arise as byproducts and waste materials from various industries [8,11]. Recently, researchers have reported that materials with biological and natural origins, such as agricultural, banana peel, peel waste, and animal waste, are effective and usable in the removal of metals [9,[12][13][14][15][16]. Some sorbents such as seaweed (Gymnogongrus Torulosus) [17], leaf powder (Ficus religiosa) [18], and bacteria (Tannery Effluents Contaminated Soil) [19] were used for metal removal.…”

Peach stones valorizated to high efficient biosorbent for hexavalent chromium removal from aqueous solution: adsorption kinetics, equilibrium and thermodynamic studies

“…The increase in adsorption capacity of the RPS biosorbent with increasing Cr(VI) concentration was due to higher probability of collision between Cr(VI) ions and RPS biosorbent, increased driving force of the concentration gradient. 28,29 As is seen in Fig. 5b, the percentage removal then depended upon the initial concentration.…”