커피찌꺼기에 흡착된 은 이온의 탈착 및 재생 특성

Abstract

질산, ethylene diamine triacetic acid (EDTA) 그리고 nitrilo triacetic acid (NTA)을 이용하여 폐기물인 커피찌꺼기에 흡착된 은 이온에 대한 탈착 특성을 조사하였다. 1.0 M의 질산용액을 이용하였을 때 가장 높은 97.8 %의 탈착율을 얻을 수 있었다. 또한, S/L 비가 1.0 이하일 경우, 커피찌꺼기에 흡착된 은 이온은 약 98~100 % 탈착되어졌으며 약 60분의 시간 내에 대부분의 탈착이 일어났다. 게다가 2번의 반복된 흡착 및 탈착 공정을 거친 후의 재사용된 커피찌꺼기의 은 이온에 대한 흡착능은 약 43.9 mg/g으로서 재사용전의 커피찌꺼기의 흡착능인 45.9 mg/g에 비해서 약 4.4%의 감소율을 보였다. This experiment was conducted to test desorption and recycling characteristics for silver ion adsorbed into waste coffee grounds by using various desorbing agents such as nitric acid, ethylene diamine triacetic acid (EDTA) and nitrilo triacetic acid (NTA). It is appeared that the highest desorption efficiency for silver ions was obtained as about 97.8 % by 1.0 M of nitric acid solution. Also, in the case of less than 1.0 of the ratio of solid and liquid (S/L) (g/L), silver ions adsorbed onto coffee grounds was desorbed as about 98~100 %, and most of desorption process was completed within 60min. In addition, adsorption capacity of reused waste coffee grounds for silver ions was highly maintained as about 43.9 mg/g until the <TEX>$2^{nd}$</TEX> cycle, as compared with the adsorption capacity with 45.9 mg/g of the adsorption capacity for virgin waste coffee grounds.