The aim of this work is to make a brief review of the adsorption of CO2 on modified clay minerals. Previous researchers have used different clay modifications, either by making changes in the structure by a reaction with another product or by the addition of a catalyst to improve their CO2 adsorption capacity. In order to obtain high values of CO2 uptake, some researchers have been incorporated amines-speices such as (3-aminopropyl)triethoxysilane (APTES), tetraethylenepentamine (TEPA) and a branched polyethylenimine (PEI) by grafting or impregnation. The synthesis of an adsorbent from mineral clays can generate an increase in its porosity and in its textural properties. These investigations differ in a number of factors such as the kind of clay, the operating conditions, y and the nature of the impregnated compound. The role of these factors in the CO2 adsorption capacity will be considered in detail in this review.
The synthesis of PCH from natural bentonite produces a porous heterostructure material effective for the adsorption of glyphosate from water. The adsorption process takes place through an interaction between the silanol group of montmorillonite and/or the PCH adsorbent with the functional groups of glyphosate. The glyphosate adsorption isotherms, recorded for all the studied samples, have been established to be of Langmuir type. The kinetic of the herbicide adsorption on the PCH was best described by the pseudo-second-order model. With the increase in temperature from 25 to 50 °C, the sorption capacities of the materials studied towards glyphosate increased. The process of glyphosate adsorption was found to be endothermic and spontaneous in nature, as indicated by positive values of ΔH and negative values of ΔG. According to the results obtained, the herbicide sorption was more effective in a basic environment. The maximum amount of adsorbed glyphosate is almost doubled with PCH from 13.5 mg/g of natural clay to 27.5 mg/g of PCH.
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