Isolation of humic acid from peat soil and its application as an adsorbent for AuCl4− in solution

Abstract

Abstract. Humic acid (HA) has been isolated from South Kalimantan (Indonesia) peat soil using alkali extraction method. The isolated HA then was applied on the adsorption process of AuCl 4 -in solution. Parameters investigated in the adsorption process consisted of the effect of initial pH, adsorption rate constant (k) and the adsorption capacity of AuCl 4 -on peat soil HA. The adsorption rate constant was determined according to the kinetic model proposed by Santosa (2007). The adsorption of AuCl 4 -on peat soil HA was optimum at pH 2. The adsorption rate constant (k) was 1.11 x 10 -3 min -1 . Adsorption of AuCl 4 -on peat soil HA fitted the Langmuir isotherm with the adsorption capacity of 90.91 mg.g -1 . The adsorption of AuCl 4 -on peat soil HA was accompanied by the reduction of AuCl 4 -to Au(0), clarified by the existence of several peaks belonging to Au(0) in the XRD pattern of HA after the adsorption process.

Potential of Baltic Region Peat in High Added-value Products and Environmentally Friendly Applications - A Review

“…In order to reduce the presence of mineral particles in solid residue Machado et al [85], Klavins and Purmalis [86], [87], Lodygin et al [80], Lestari [96], Klavins et al [88] the solid part after centrifugation was suspended in a mixture of 0.1 M HCl and 0.3 M HF. This process was repeated until the ash content of HS was reduced to 2 % [86]- [88] or until the ash content of HA is < 1 % [96]. Then the precipitate was washed in deionised water [85] / distilled water [86], [88], [93], [96] until negative Cltest.…”

“…This process was repeated until the ash content of HS was reduced to 2 % [86]- [88] or until the ash content of HA is < 1 % [96]. Then the precipitate was washed in deionised water [85] / distilled water [86], [88], [93], [96] until negative Cltest. The Clpresence controlled by AgNO3 solution [85], [93], [97].…”