1. Organic modification
MMT organic modification is an organic process of introducing organic modifiers into the MMT crystal layer. Common organic modifiers are quaternary ammonium salts and amine compounds, such as dodecyl trimethyl bromide (DTAB), hexadecyl Cylpyridine (CPB). After modification, the layer spacing of MMT increases, the pores increase, and it has a larger specific surface area than natural MMT, which is conducive to improving the adsorption effect on mycotoxins and heavy metals. MMT has also changed from a single hydrophilicity to both lipophilicity and hydrophilicity. Appropriate modification will also reduce the adsorption rate of MMT to amino acids, vitamins and other nutrients, and increase the desorption rate of nutrients.
2. Inorganic modification
MMT inorganic modification refers to the use of MMT expansion, adsorption and the exchangeability of interlayer cations to introduce water and hydroxyl polymerized metal cations into the interlayer, and then dehydroxylate or dehydrogenate by heating to form a columnar A new substance with a columnar structure of metal oxide clusters. In the inorganic modification of MMT, the choice of modifier is very important, and polynuclear metal cations such as aluminum hydroxide and iron hydroxyl are the most ideal modifiers. The MMT modified by metal cations forms pillars, the interlayer spacing increases, and the adsorption capacity for antibiotics and mycotoxins is enhanced. Studies have shown that inorganically modified MMT also has antibacterial function.
3. Composite modification
The composite modification of MMT refers to the fact that two or more inorganic and organic modified molecules or ions enter the MMT interlayer domain environment, and form a composite pillared MMT through the pillaring effect, which shows synergy and has various special properties. modification method. Organically modified MMT forms flexible pillars between layers, while inorganic modification forms rigid pillars. Composite modified MMT combines the properties of more than two pillars, and has certain advantages over a single pillar. At present, composite modified MMT is widely used in industrial wastewater. Composite modification of MMT with aluminum chloride, lanthanum chloride and cetylpyridine significantly enhanced the removal capacity of benzopyrene and p-chlorophenol in wastewater, and was superior to activated carbon. The inorganic-organic composite MMT prepared by this method can remove up to 97.57% of the orange Ⅱ dye in the leather industry wastewater. MMT was modified with polyhydroxyaluminum and cetyltrimethylammonium, and the adsorption efficiency of modified MMT for arsenic was as high as 99%.
FAQ
What are the differences between organic and inorganic modifications of montmorillonite?
The primary differences lie in the modifiers used, structural changes, and target applications:
Organic Modification: Involves introducing organic modifiers (such as quaternary ammonium salts or amine compounds like DTAB and CPB) into the MMT crystal layers. This process increases layer spacing and pore sizes, shifts the mineral from strictly hydrophilic to both lipophilic and hydrophilic, and maximizes its specific surface area. It is highly effective for absorbing heavy metals and mycotoxins without absorbing vital nutrients like vitamins and amino acids.
Inorganic Modification: Uses MMT’s expansion and cation exchange properties to introduce polymerized metal cations (such as aluminum hydroxide or iron hydroxyl) between the layers, which are then heated to form rigid metal oxide clusters. This creates a “pillared” columnar structure that significantly boosts its ability to adsorb antibiotics and mycotoxins while introducing new antibacterial properties.
What is composite modification of montmorillonite, and where is it primarily applied?
Composite modification combines both inorganic and organic molecules or ions within the MMT interlayer domain, blending the flexible pillaring effect of organic modifiers with the rigid pillaring effect of inorganic modifiers. This creates a synergistic material with multiple specialized properties.
