Chapter 13
Apatite
CARBONS PREPARED FROM BAMBOO
Most bamboos contain large amounts of ligneous fiber and can therefore be carbonized into chars, which can be used in decoration, in purifying drinking water, for indoor air filtering, dehumidifying, thermal insulation, electromagnetic wave shielding, etc. However, bamboo is rarely used as the raw material for activated carbon. Meso bamboo is grown profusely in Taiwan. Its stem diameter can reach up to 15 cm. In earlier days, it was commonly used for building, furniture, eating and cooking utensils, foods, and food processes. Lately, there only use that seems to have remained, is that of using bamboo shoots for food. It is regrettable that the mature bamboo does not seem to have many uses any more. Since the utility value of bamboo has greatly dropped, bamboo-growing has mostly been abandoned reducing the number of plants. The reduction in the number of bamboos grown has caused severe ecological damage to the environment and to water-soil conservation.
Bamboo grows fast, absorbing, CO2 from the atmosphere at great speed, so it effectively helps to slow down global greenhouse effect. In previous studies, oak, bamboo, coconut shell, and cedar were activated with steam to obtain activated carbons. The results showed that physical properties (BET surface area and pore volume) and adsorption capacities (chloroform adsorption) of the activated carbons derived from bamboo were lower than those from the other three raw materials Furthermore, studies have shown that of the carbons derived from bamboo dust, coconut shells, groundnut shells, rice husks, and straw, straw carbonhas the highest adsorption capacity being 5.9 times that of bamboo dust carbon, which is the lowest . From this evidence it is clear that it is not easy to make good activated carbon from bamboo. The aim was to prepare porous carbons from Meso bamboo using KOH etching and CO2 gasification processes. The physical properties of the carbons, namely the BET surface area, pore size distribution, and the total pore volume were compared. Their capacities for the adsorption of basic blue 1, methylene blue, p-cresol, p-chlorophenol, p-nitrophenol, and phenol from water were systematically investigated.
1. Meso bamboo char was removed, crushed, and sieved to a uniform size ranging from 0.83 to 1.65 mm. These powders were well mixed with water and KOH in stainless steel beakers with water/KOH/char weight Meso bamboo was first carbonized for 1.5 h at 450 o C, then soaked in KOH solutions with KOH/char ratios of 0.5, 1, 2, and 3. Three kinds of activation processes, no, low, and high CO2, were used. Carbons activated under high CO2 conditions exhibited high BET surface areas ranging from 1627 to 2444 m 2 g -1 .
The adsorption of methylene blue, basic brown 1, p-nitrophenol, p-chlorophenol, p-cresol and phenol from water at 30 o C on the activated carbons was studied. All adsorption equilibrium isotherms were in agreement with the Langmuir equation, and were used to compare the adsorption of covered areas (Sc/Sp) of the activated carbons with the different combinations of CO2 gasification and KOH/char ratios. In this research, activated carbons with high surface area were obtained from Meso bamboo having excellent adsorption capacity for dyes and phenols ratios of 1/0.5/1, 1/1/1, 2/2/1, and 2/3/1.
REFERENCES
Removal of basic dye from wastewater using parthenium hysterophorus l. as an adsorbent hem lata, and r.k. gupta v.k. garg Proceedings The 4th Pacific Basin Conference on Adsorption Science and Technology Tianjin China May 2 1-25 2006
Sorption of reactive red dye 4 onto a beer-waste biosorbentcui longzhe*, wu guiping, deng kejian Proceedings The 4th Pacific Basin Conference on Adsorption Science and Technology Tianjin China May 2 1-25 2006
Leah J. Matheson, Ph.D. (leahm@mse-ta.com), William C. Goldberg, P.E., and Gordon J. Huddleston (MSE Technology Applications, Inc., Butte, MT)William D. Bostick, Ph.D. (Materials and Chemistry Laboratory, Inc., Oak Ridge, TN)
Effect of humic acids on heavy metal removal by zero-valent iron Jan Dries An Kemps, Josef Trögl, Leen Bastiaens, and Ludo Diels (ludo.diels@vito.be) (VITO)
Spyros N. Agathos (UCL)
Competitive sorption and desorption of phenols in surfactant-modified clays, Won Sik Shin and Young Kyu Kim, Ji-Hoon Kim, Young-HunKim, Young Woong Jeon and Dong-Ik Song
Adsorption of dyes and phenols onto high surface Area carbons prepared from bamboo using koh Etching and co2 gasification,Feng-chin wu, wei-feng chang ru-ling tseng
Proceedings The 4th Pacific Basin Conference on Adsorption Science and Technology Tianjin China May 2 1-25 2006