Adsorption of Ag⁺ from Aqueous Solutions by Rice Husk

Abstract

This paper reports the feasibility of using rice husk to remove Ag+ from synthetic wastewater. Effect of various adsorption parameters, namely, pH, adsorbent dose, initial silver concentration and contact time has been studied in batch systems. The results indicated that rice husk offered high removal efficiency, fast adsorption rate and high uptake capacity for Ag+ ions. The equilibrium was attained within 20 min and the maximum removal efficiency at 11g/L rice husk and at pH 2 was found to be 99.76%. The kinetic data was fitted well to pseudo-second order model. The isotherm adsorption data was well described by the Langmuir isotherm model and the maximum uptake capacity of Ag+ ions onto rice husk was found to be 42.43 mg/g.

Rice Husk-Based Adsorbents for Removal of Metals from Aqueous Solutions

“…According to the calculated kinetic data, the process was described by the pseudosecond-order kinetic model, i.e., the rate-limiting step was chemical adsorption. The studied adsorption process is described well by the Langmuir model [62]. The same result was found in [63].…”

“…Luo et al [62] and Liang et al [63] investigated Ag + ions' adsorption using rice husk and expansion-treated rice husk powder produced by Haitian High-Tech Material Co., Ltd., without added purification, respectively. In [62], the effects of the pH (1-6), adsorbent mass (0.1-1.3g), initial silver concentration (50-2000 mg dm −3 ), and contact time (1-135 min) have been studied during batch experiments (volume Ag + solution-100 cm −3 , stirring speed-180 rpm, and temperature-25 • C). The greatest Ag + removal percentage (96.13%) by 0.5 g of rice husk from a 10 mg•dm −3 silver solution was at pH 1, and its lowest value (51.92%) was at pH 4.…”

“…Modification and activation of rice husk by the action of organic and/or inorganic compounds [30][31][32][33][34]36,[38][39][40]43,44,47,49 Sorbents based on rice husk have been tested in the adsorption processes of nonferrous , ferrous [40,41,51], minor [35][36][37][38][39][40]45,46,[52][53][54][55][56][57][58][59], radioactive [60,61], precious [62][63][64][65][66][67][68]74], rare, and rare-earth metals [35,[69][70][71][72]. The main task solved during the research was the purification of wastewater and natural objects from toxic metals.…”

The Studies of Adsorption of Heavy Metal Ions of Lead andCopper by Distillers' Grains

“…The removal efficiency for Pb 2+ and Cu 2+ , respectively, arrives at a balance of 96 and 77% within 1 and 5 minutes and remains relatively constant thereafter. This rapid performance suggests the good diffusion ability of Pb 2+ and Cu 2+ in aqueous solutions and good binding capacity between the metal ions and the surface of distillers' grains [7].…”

Studies on Adsorption of Strontium (II) by Expanded Rice Husk

“…The expanded rice husk, which is a ideal biological adsorbent due to its properties of the low price, low secondary pollution, easy recycling of metal elements [6][7], is used to remove Sr 2+, one of simulated radionuclides, from the simulated radioactive wastewater in this paper.…”