Although montmorillonite can use its own characteristics to remove pollutants in water, the hydrophilic inorganic ions in the interlayer of montmorillonite make it less selective for organic pollutants in water.
At present, montmorillonite is mainly used to absorb organic pollutants by means of modification and inorganic pillars; organically modified montmorillonite surface is hydrophobic, which is a good absorbent for hydrophobic organic pollutants. ; Column immersion montmorillonite can be used for inorganic pollutants.
There are many kinds of harmful substances in wastewater, and a single harmful montmorillonite exists from time to time in the wastewater of many pollutants. It has good performance for a certain performance, and it has a variety of transformation methods. Combined use can effectively improve the ability of high montmorillonite to remove pollutants in water and improve its reuse ability.
Inorganic salt modification is through ion exchange between montmorillonite (MMT) interlayer cations and one or more inorganic metal hydrated cations. While the hydrated cations balance the negative charges on the silicon-oxygen tetrahedron, they work together with the interlayer solvent to make the montmorillonite (MMT) The de-soil is peeled off and dispersed into a single wafer, which improves the adsorption capacity of MMT to pollutants in water.
However, inorganic salt-modified montmorillonite only shows great affinity for oxygen-containing anions in water, and does not show a particularly strong adsorption capacity for phosphate ions, while organic surfactant-modified montmorillonite can significantly Improve the adsorption selectivity of montmorillonite to heavy metals, but it will cause the pore structure of montmorillonite to be blocked, which will reduce the pore volume and specific surface area, which is not conducive to the adsorption of pollutants.
Therefore, the researchers first metal intercalated, calcined montmorillonite, then propped montmorillonite, and then propped montmorillonite supported montmorillonite surfactant or silane coupling agent for secondary modification to prepare inorganic organic soil.
Inorganic-organic composite modification mainly uses surfactants or organosilanes as organic modifiers, and polymerized hydroxyl metal ions as inorganic pillar propping agents. The obtained organic-inorganic composite modified montmorillonite contains both organic and inorganic types. The active group not only has the mechanical structure and stabilizing effect of pillared montmorillonite, but also has the hydrophobic effect of organic montmorillonite, has a large pore volume and specific surface area, and has good adsorption selectivity for heavy metal ions. Synergistic adsorption of organic pollutants can also be achieved.
The hydrated cations of inorganic metals are ion-exchanged with the interlayer cations of the montmorillonite, so that the montmorillonite is peeled off and dispersed, and then the inorganic pillared montmorillonite with a large layer spacing is formed by roasting, and the organic surfactant enters the montmorillonite layer. Formation of inorganic-organic modified montmorillonite.
