Analysis of kinetic and equilibrium adsorption of heavy metals by natural materials

Abstract

One of the effective methods of cleaning up water is an adsorption method. The adsorption treatment is effectively used as a post-treatment after using treatment chemicals precipitators. You can use natural porous carbon-containing materials as obtained sorbents, as industrial waste, or cheap carbon raw modified by humans: ash, fines coconut, peat, activated carbon, active clay, bio- and phyto-sorbents, agricultural wastes (rice, barley, wheat husk, nutshells, bagasse, etc.). In this regard, there is a question of finding cheap natural sorbents with a high adsorption capacity. In this article we studied the regularity of extraction of heavy metal cations Cu2+, Co3+, Ni2+, Fe3+ from aqueous solutions, using natural sorbents: husk cedar cones, pine nut meal, walnut partitions, pectin. Constancy of the concentration of heavy metal ions in the solution corresponds to the time of adsorption equilibrium (from 10 to 40 minutes). High adsorption capacity with respect to heavy metal ions showed pectin and proteinaceous materials. It is shown that the adsorption capacity of natural raw materials in relation to heavy metal ions increases by 20-30% due to modification of the surface of biosorbents. The degree of metals extraction from solution using a composition based on a peel cedar cones and pectin increases by 20-30% in comparison with pure husk of a cedar cone. According to the degree of extraction from the aqueous solution, metal ions are arranged in the row Fe3+>Co3+>Ni2+>Cu2+.

Interparticle diffusion and thermodynamic modeling studies for the removal of heavy metals using mixed adsorbents in industrial effluents

“…where R is the universal gas constant (8.314 J mol −1 K −1 ), T is the temperature in Kelvin and K c is the equilibrium/rate constant calculated as the surface and solution metal distribution ratio. The negative values of G o indicate the spontaneous nature of the adsorption process (Salishcheva et al., 2021). However, the negative value of G o decreases with an increase in temperature, which indicates that the spontaneous nature of adsorption was inversely proportional to the temperature (Kumar et al., 2018; Sahmoune, 2019).…”

Removal of chromium and Iron using mixed adsorbent for synthetic and industrial samples in a continuous column reactor

“…The different type of trend for chromium was observed at fixed bed height of 36 cm (150 g) and different volumetric flow rates of 10, 20, and 30 ml/min [22][23].The more % removal was observed for industrial samples having 96.2%, 72.63%, and 81.77% in comparison with synthetic effluents having 98.8%, 87.91%, and 98.71% which was due to the presence of other heavy metals, sludges apart from competitive adsorption of chromium present in the industrial effluent [24][25].Overall in comparison with industrial effluents for iron, the synthetic solutions have proved to be more superior in terms of total % removal and better performance was observed with synthetic solutions rather than industrial effluents for iron as shown in Tables 3 and 4 respectively. For a similar comparison studies with chromium, the industrial effluents proved to be more percentage removal as compared to synthetic solutions [23][24][25].…”

Rice Husk Cellulose-Based Adsorbent to Extract Rare Metals: Preparing and Properties

“…Adsorption is considered to be one of the rather cheap and simple techniques to apply not only in the purification processes of various aqueous systems but also in hydrometallurgy [13][14][15][16][17][18][19][20][21][22][23][24][25], including rare earth element (REE) technology [26][27][28]. In recent years, the creation of sorbents based on waste materials, in particular those of plant nature, has represented a broad independent research direction [29][30][31][32][33][34][35][36][37][38][39][40][41][42][43]. However, as noted by Anastopoulos et al in their paper [27], there are practically no review materials on REEs adsorption by biosorbents.…”