木質纖維材料化學改良對於過濾系統之影響(3/4)-Removal of pollutants from Agueoues Solutions by Lignocellulose Wastes

The ability of five spices of bamboo waste and known biosorbents to remove metal ions from aqueous solutions at different reaction time, particle size and pH values was determined by inductively coupled plasma atomic emission spectroscopy (ICP-AES) in 2005. The results showed that the adsorption efficacy increased with reaction time and after 4~8h, the adsorption of four metal ions reached equilibrium. The optimum pH for metal adsorption is at the range of 4~6. Among these five compared materials, activated carbon was the most effective, and then was exhausted coffee, exhausted tea and bark, and the last was bamboo (Dl). The metal removal efficiency of raw bamboo can be greatly and easily improved by water extracted treatments and the results are even better than those of bark, exhausted coffee and tea. This is because bamboo extracted with water can effectively increase its available volumes and surface area and more metal-binding functional groups were released, resulted in better metal removal efficiency. Chemical modification was conducted in 2006 to improve the heavy metal removal ability of bamboo. Phyllostachys pubescens was sampled, grounded, sieved, air-dried, and then treated by NaOH, citric acid、tartaric acid、oxalic acid and malic acid.
It is interesting to find that the removal ability of bamboo has already been improved in the defiber process by NaOH: from 30% to 95% (copper ion); from 5% to 49% (cadmium ion). Among all testing chemical agent, tartaric acid modified bamboo showed the best improving ability, and then oxalic acid. The Pb removal ability of tartaric acid modified bamboo (98%) was almost equal to commercial active charcoal (100%). As to nickel, copper, cadmium removal ability, tartaric acid modified bamboo also showed 20 times greater than untreated bamboo. Tartaric acid modified bamboo is a potential material to the follow-up field test.
In 2007, the comparison of metal-removal ability between continuous adsorption on a packed column and batch wise experiment will be conducted. Samples from different fields will also be adopted.