Leaching Behavior of Copper, Zinc and Lead from Contaminated Soil with Citric Acid

Abstract

Soil samples contaminated with heavy metals such as lead (Pb), copper (Cu) and zinc (Zn) were leached with citric acid solution. A five step-sequential extraction method involving "exchangeable", "bound to carbonate", "bound to FeMn oxide", "bound to organic matter" and "residue" fractions was also carried out to investigate the leaching behavior of Pb, Cu and Zn with citric acid.The leaching efficiencies of Pb, Cu and Zn increased with increasing citric acid concentration. About 86.5, 88.9 and 83.3% leaching efficiencies were obtained for Cu, Zn and Pb, respectively, under the following leaching condition: 2 kmol·m ¹3 in citric acid concentration, 120 min in leaching time, 10% in pulp density, 50°C in temperature, and 80 rpm in shaking speed. In the sequential extraction test, the heavy metal contaminants were extracted more in "bound to carbonate" and "bound to FeMn oxide" fractions than in "bound to organic matter" and "residue" fractions. When the leaching efficiencies of Pb, Cu and Zn with 2 kmol·m ¹3 citric acid solution were compared with the results of the sequential extraction, a good agreement with the summation of amount leached in "exchangeable", "bound to carbonate" and "bound to FeMn oxide" fractions was noted.

Remediation of inorganic and organic contaminants in military ranges

“…Soil samples from two military sites in Korea contaminated with heavy metals, such as Pb, copper (Cu) and zinc (Zn), were leached with citric acid solution. Leaching efficiencies of approximately 86.5, 88.9 and 83.3 % were obtained for Cu, Zn and Pb, respectively which also increased with increasing citric acid concentration (Park et al 2013). A sequential extraction test revealed that the heavy metal contaminants were predominantly associated with the carbonate and Fe-Mn fractions compared with the organic matter and residue fractions of the soil.…”

The Determination of Chemical Forms of Heavy Metals in Shooting Area Contaminated Soil Using Sequential Extraction Method

“…사격장 부지의 토양은 납, 구리, 아연 등의 중금속과 hexahydro -1,3,5-trinitro1,3,5-triazine(RDX), 2,4,6-trinitrotoluene(TNT), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX) 등의 화약류로 오염된다. 토양 중 화약류성분은 자연적으로 분 해될 가능성이 있으나 중금속 성분의 경우 미생물에 의한 생화학적 분해를 기대하기 어렵다 (Kirpichtchikova et al, 2006;Park et al, 2013;Singh, 2012 ), 아연(7.14 g cm −3…”

“…그러나 공기중에서 산소나 이산화탄소와 반응하여 산 화물이나 탄산염으로 풍화된 중금속은 화학적 침출에 의 하여 제거되기 용이하다 (Lin et al, 1995;Lin, 1996;Park et al, 2013). 따라서, 풍화된 형태와 풍화되지 않은 형태를 동시에 함유한 토양오염의 경우는 비중선별 등의 광물처리공정 후 화학적 침출공정에 의해 처리되어야 한 다 (Mercier et al, 2002).…”

Removal of Zn from Contaminated Sediment by FeCl3 in HCl Solution

“…One of the most widely used methods is the Tessier sequential extraction method which consists of five extraction steps: "bound to exchangeable", "bound to carbonate", "bound to oxide", "bound to sulfide or organic matter", and residue. A study conducted by Park et al on the leaching of heavy metals (Cu, Zn, Pb) from contaminated soil using citric acid revealed that the metals in carbonate and oxide phases are easy to dissolve [2].…”

“…Various treatment methods have been proposed for remediating contaminated sites, such as gravity separation, phytoremediation, thermal processing, solidification/stabilization, electrokinetic remediation, and soil washing [1,2]. Gravity separation techniques have been considered to be cost-effective and environmentally friendly primarily because of the chemical-free process, but their effectiveness and applicability are rather difficult in the treatment of fine concentrates with particle sizes less than 75 μm [2]. Since fine particles have high specific surface area, chemical treatment methods such as leaching generally are more suitable than physical treatment processes.…”