Adsorptive Recovery of Au(III) from Aqueous Solution Using Modified Bagasse Biosorbent

Abstract

Abstract-The recovery of Au(III) from aqueous chloride solutions onto modified bagasse biosorbent was investigated. The parameters for biosorbent preparation as well as gold recovery were studied in detail. It was found that 99.8 % of sugarcane bagasse could be modified as biosorbent having better physical properties for adsorption. The solution pH, sorbent dosage, initial Au(III) concentration and temperature were the studied variables that affect the efficiency of gold recovery as well as adsorption behavior. The efficiency of 99% for Au(III) recovery was obtained under the following conditions: 25 mg sorbent, 25 mL of 25-500 mg/L Au(III), pH 2, 150 rpm, 4 h and 25 o C. The 99% of gold recovery still obtained in only 1 h or less with the increasing of dosage or temperature. The gold adsorption in this study was best fitted with Langmuir isotherm model and the maximum capacity for gold loading was determined to be 1497.5 mg/g or 7.6 mmol/g. The adsorption kinetics was also evaluated in terms of the pseudo first-order and pseudo second-order kinetic models. The high activation energy of 45.8 kJ/mol was estimated which represents a chemisorption process. The adsorption mechanism in this study is clarified to be the oxidation of hydroxyl to carbonyl in biosorbent and reduction of trivalent gold ions to metallic gold simultaneously on biosorbent surface. The results from ORP measurement, FT-IR and EDS spectra including SEM images were the supported evidence for this adsorption mechanism. The modified bagasse biosorbent therefore has potential in gold recovery process.Index Terms-Au(III) recovery, modified bagasse, biosorbent.

Characterization of Sweetmeat Waste and Its Suitability for Sorption of As(III) in Aqueous Media

“…Metal uptake using biomass is proved to be advantageous due to their high sequestration capacity and heavy metal selectivity (Volesky and Holan, 1995). These biosorbents are also regenerative (Figueira et al, 1999) and capable of recovery of precious metals from wastewater (Rubcumintara, 2015). Keeping in view the origin of SMW, which is derived from the combination of flour, sugar, and fatty acids, it is expected that the above-mentioned functional groups would be present, which may play a vital role in metal removal from wastewater.…”

Modification of Silica Coated on Iron Sand Magnetic Material with Chitosan for Adsorption of Au(III)

“…Modification of MM surface using silica and chitosan prevents the protonation of amine groups and causes low solubility. Under acidic condition (pH 1-2) after chitosan dissolved, the acid solution contacts to the silica and forms Si(OH) 4 leading to break Fe-O-Si bond. The surface of the magnetic material that is not protected contacts directly to the acid, and make iron ion to dissolve.…”

“…Nowadays, the consumption of gold has increased, this condition encourage researchers to develop gold isolation method. There are several methods to uptake gold from aqueous solution, such as solvent extraction, precipitation and adsorption [4].…”

Thermodynamics and Kinetics of Au(III) and Ag(I) Sorption on to Silicon-Organic Polymer

“…These values suggest that the sorption of Au(III) and Ag(I) onto PSTM-3T is a chemical sorption, which is in accordance with the magnitude of activation energy for chemical adsorption. The activation energy of chemical adsorption is usually between 8.4 to 83.7 kJ/mol [12,13].…”