Characteristics of adsorption of rice-hull activated carbon

Abstract

An experiment was conducted to compare the adsorption capacity and characteristics between activated carbon made of rice-hull(RHAC) and F-400 by Calgon to remove phenol, heavy metal and ammonia-nitrogen. While F-400 could not remove ammonia-nitrogen, RHAC was able to adsorb it. This is considered to be due to the ionic sorption capability of SiO2 remaining on the surface of RHAC. From the sorption equilibrium test, it was found that RHAC has higher adsorption capacity than F-400. In column tests, the slope of breakthrough curves of RHAC which represent the affinity of an adsorbent, was observed to be more gradual than F-400. This may be attributed to the inner diffusion of adsorbent once attached on macropores, into micropores well developed, with higher specific surface area of RHAC than F-400. For heavy metals, F-400 would remove chromium and lead but not cadmium, whereas RHAC was able to remove cadmium, lead but not chromium. This phenomenon is considered to have something to do with the distinct surface functional group of RHAC and the various surface charge densities of heavy metals tested.

Adsorption of chromium (III) ion from aqueous solution using rice hull ash

“…Adsorption is an efficient method to clean chromium (III) ions (Tarasevich and Klimova, 1999) and activated carbon is a widely employed adsorbent to remove it (Candela et al, 1995). However, because of the high cost of activated carbon, the possibilities of several wastes such as red mud (Gupta et al, 2001a) activated slag (Srivastava et al, 1997), activated carbon developed from fertilizer waste material (Srivastava et al, 1996), green algae spirogyra species (Gupta et al, 2001b), spent bleaching clay (Seng et al, 2001), bagasse fly ash (Gupta et al, 1999;Gupta and Ali, 2004) as well as rice hull and its derivatives (Kim and Choi, 1998;Srinivasan et al, 1988) have been investigated to replace it.…”

“…This finding encourages us to explore the possibility of using this low cost RHA to uptake chromium (III) ion from aqueous solution. Unfortunately, reports on the performance of the rice hull or its derivatives to remove Cr 3+ are scarce in the literature (Kim and Choi, 1998;Srinivasan et al, 1988). Srinivasan et al (1988) prepared their activated carbon from rice hull by treating it with sulphuric acid and then activating it by air.…”

Lead uptake by new silica-carbon nanoparticles

“…The equilibrium data were well fitted in terms of the Freundlich and Langmuir adsorption isotherm models. The maximum adsorption capacity was relatively higher than other adsorbent material (Table 7) [38][39][40][41][42] and found to be 385 mg/g (1.86 mmol/g). The thermodynamic parameters have been obtained, and showed that the sorption process of SCNP onto lead was spontaneous and exothermic.…”

Renewable Silica-Carbon Nanocomposite and Its Use for Reinforcing Synthetic Wood Made of Rice Straw Powders

“…The renewable silica powder is mailny amorphous and more reactive than silica powder of crystalline quarts minerals. Instead of amorphous silica powder, the rice husk and straw wastes can produce active carbon powders having high surface area [2]. The ratio contents of silica and carbon of the burned high siliconeous biomasses depend on pre-teatments, burning temperatures and length of burning as reported previously by some researchers [3,4].…”