Research on the Adsorption of Heavy Metal Ions from Model Solutions by Humic Acids Isolated from Sapropel

Abstract

The article presents the results of research on adsorption of Cu2+, Ni2+ and Pb2+ ions from model solutions with concentrations of 2–25 mg/dm3 under static conditions using humic acids isolated from the sapropel of Lake Lipovo, Novgorod region as an adsorbent. Adsorption equilibrium in the model solution-adsorbent systems occurs in 2 hours. The kinetic curves of adsorption of Cu2+, Ni2+ and Pb2+ ions from model solutions by humic acids are described with a pseudo-second order kinetic model; consequently, the limiting stage of the adsorption process is the chemical interaction between heavy metal ions and functional groups of humic acids in a 1:1 ratio. The kinetic constants of the adsorption of heavy metal ions by humic acids have been calculated. It was found that the adsorption of Cu2+, Ni2+ and Pb2+ ions occurs on the surface of the sorbent; the Langmuir equation is most acceptable for describing the process. The constants of adsorption equilibrium in the model solution-sorbent systems are calculated according to the Langmuir equation. The study of the adsorption of heavy metal ions on humic acids isolated from the sapropel of Lake Lipovo, Novgorod region, has shown the perspective of using sorbents for purifying industrial wastewaters.

Removal of Ni(II) and Cu(II) in Aqueous Solutions Using Treated Water Hyacinth (Eichhornia crassipes) as Bioadsorbent

“…In the reports where they used WLW, adsorption capacities of 0.2899 [40] and 39.6 mg/g [71] were obtained. In terms of what has been reported in the literature for Cu(II) adsorption using adsorbents such as Zn-Cl2-activated carbon [64], chitosan [34], DCDP [34], sapropel humic acids [58], almond [39], peanut shell [37], charred bones, and bentonite [52], the reported adsorption capacities were between 6.07 and 195.88 mg/g. When comparing the adsorption capacities of WLW and carbonized water lily as adsorbents, the latter had a slightly higher adsorption capacity of 24.3 mg/g [73], compared to WLW with an adsorption capacity of 23 mg/g [67].…”

“…In other studies that have used different adsorbents, the adsorption capacity has been found to be between 0.256 and 190.38 mg/g using CoFeO 2 /SO 2 nanoparticles [54], magnetized graphene [56], magnetite-bentonite nanocomposites [57], sapropel humic acids [58], calcium carbonate in bacterial magnetosomes [36], hydroxyapatite [59], lemon peel [60], bamboo modified with mercaptoacetic acid and carbon disulfide [61], wheat and rice biochar [46], charred bones [62], and charcoal [63]. ©.…”

“…In terms of Cu(II) adsorption in WLW, adsorption capacities of 293.82, 209.46, and 171.88 mg/g were obtained at 30, 45, and 60 • C, respectively, with a maximum removal percentage of 51.8%. The adsorption capacities of various adsorbents, including ZnCl 2activated carbon [64], almond shell [39], CoFeO 2 /SO 2 nanoparticles [55], bamboo modified with mercaptoacetic acid and carbon disulfide [61], magnetite-bentonite nanocomposites [15], lime shell [65], peanut shell [40], charcoal [60,61], hydroxyapatite [59], charred bones [62], sapropel humic acids [58], calcium alginate beads immobilized on rice bran [66], residual sludge [46], bentonite [43], and bentonite pretreated with CaCl 2 [52], ranged from 2.44 to 128.21 mg/g. These adsorbents used the Langmuir model to describe the adsorption of Cu(II) on their surfaces.…”

“…These results demonstrated that the adsorption capacity of water lily as an adsorbent could be significantly improved with appropriate modification and activation. For the adsorption of Ni, there are reports in the literature about the use of different adsorbents for the removal of Ni(II), such as chitosan [34], magnetized graphene [54], sapropel humic acids [58], modified sediment [46], charred bones [62], and palm activated carbon with magnetite particles [38], with adsorption capacities ranging from 3.66 to 50.68 mg/g. In the reports where they used WLW, adsorption capacities of 0.2899 [40] and 39.6 mg/g [71] were obtained.…”