Preparation of porous bio-char and activated carbon from rice husk by leaching ash and chemical activation

Abstract

Preparation porous bio-char and activated carbon from rice husk char study has been conducted in this study. Rice husk char contains high amount silica that retards the porousness of bio-char. Porousness of rice husk char could be enhanced by removing the silica from char and applying heat at high temperature. Furthermore, the char is activated by using chemical activation under high temperature. In this study no inert media is used. The study is conducted at low oxygen environment by applying biomass for consuming oxygen inside reactor and double crucible method (one crucible inside another) is applied to prevent intrusion of oxygen into the char. The study results shows that porous carbon is prepared successfully without using any inert media. The adsorption capacity of material increased due to removal of silica and due to the activation with zinc chloride compared to using raw rice husk char. The surface area of porous carbon and activated carbon are found to be 28, 331 and 645 m2 g−1 for raw rice husk char, silica removed rice husk char and zinc chloride activated rice husk char, respectively. It is concluded from this study that porous bio-char and activated carbon could be prepared in normal environmental conditions instead of inert media. This study shows a method and possibility of activated carbon from agro-waste, and it could be scaled up for commercial production.

Changes in structural and chemical properties of rice husk biochar co-pyrolysed with Eppawala rock phosphate under different temperatures

“…High Si rich ash content could have resulted the low surface area or the low iodine adsorption capacity in the RHB prepared by us. Ahiduzzaman and Islam (2016) also observed few pores on the surface topography of rice husk biochar due to high Si contents in the rice husk.…”

“…Rice husk biochar (RHB) is a material which inherently composed of a poor porous structure due to presence of high amount of silica. Previous studies have tried to improve the porous structure by chemical means and applying high temperatures, around 600 °C during pyrolysis (Oh and Park, 2002;Ahiduzzaman and Islam, 2016). Few studies have attempted to improve the structural properties of biochar, by compositing it with a mineral matrix.…”

Evaluation of Characteristics of Activated Carbon from Rice Husk Impregnated with Zinc Chloride and Phosphoric Acid

“…Activated carbon investigated in this study prepared from rice husk. Rice husk char was prepared as described in [32,33]. Two grams (2 g) of rice husk char was soaked in zinc chloride solution for 24 h. Then the crucible was placed inside a muffle furnace to give a required heat treatment.…”

“…The ratio of rice husk char and activation agents were fixed after several trials. The detail methods are described in [32,33].…”

A Response Surface Methodology Approach for the Optimization of Cu2+ Removal Using Rice Husk–derived Activated Carbon

“…Heavy metals are generally considered as one of the main causes for adverse effects on human health and ecosystems due to their high cumulative toxicity in groundwater [1]. Among the well-known elements, copper is a carcinogenic and non-biodegradable transition metal and it is commonly detected in fertilizer manufacture, mineral processing industrial effluent, the leak of chemical pollutants and tan-house [2].…”