钻井泥浆膨润土改性方法
Modification method of Bentonite for drilling mud

　　大家都知道，膨润土具有良好的膨胀性，吸附性，并且能够和很多客体物质进行层间复合或插入反应，所以，他被广泛用于化工、石油、食品、交通、医药，造纸，能源，军工，环保等行业，又被称之为“万能材料”。为了满足某此行业，尤其是废水处理的需要，提高膨润土的使用效率，对膨润土进行改性是非常必要的。下面就为大家具体介绍一下膨润土的几种改性方法：

　　膨润土改性一般分为无机改性和有机改性两种。常用的膨润土改性方法有：活化改性法，通过添加改性剂改性和钠化改性法。

　　活化改性法是对膨润土进行活化，常用的酸化法，焙烧法，盐活化法，微波活化法，还原法，氧化法等，其中以酸化法和焙烧法较为常用。酸化改性是膨润土经过酸处理，可使膨润土层间的NA+，MG2+，K+，CA2+等到阳离子转变为可溶性的盐类而溶出，削弱了层间的键间，使层间距增大，形成具有微孔网格结构，比表面积大的多孔活性物质，也可除去分布于膨润土结构通道中的杂质，增大其孔容积，有利于吸附质分子的扩散，使改性后的膨润土具有较强的化学活性和物理吸附性能。

　　高温焙烧法主要迎合膨润土在不同温度下焙烧具有不同表面积的特性。膨润土受热可先失去表面水，层间吸附水及孔隙中的杂质，减小水膜和杂质产生的吸附阻力，使其吸附性得到改善。

　　添加改性剂改性是目前该领域研究的热点，可分为有机膨润土，交联膨润土和有机交联膨润土三种。有机膨润土是通过有机改性剂对天然膨润土进行改性制得的膨润土。常用的膨润土有机改性剂是季铵盐型的阳离子改性剂，其主要的作用机理是由于季铵盐阳离子进入膨润土的层间不但使有机膨润土的层间距离大，而且改善了其疏水性，从而增强了膨润土去除有机物的能力。交联膨润土孔径可调，分布均匀，具有较好的吸附性，可以用于水中离子型或非离子型污染物的处理。

　　钙膨润土的钠化方法主要有悬液法，干混合法，湿堆放法和湿挤压法等。常用的钠化剂有纯碱，烧碱。其作用原理是通过离子交换反应作用，将蒙脱石层间阳离子钙交换出来，造成正电荷亏损，由吸附在晶体外表面和晶层间的可交换性阳离子来中和平衡。

　　近年来我国对膨润土改性方面取得了一定的成就。目前，膨润土改性产品已经被研究应用于含芳香类化合物有机废水，印染废水，石油废水，含磷废水，味精废水的处理。

　　As we all know, bentonite has good expansibility, adsorption, and can be intercalated or intercalated with many guest substances. Therefore, it is widely used in chemical industry, petroleum, food, transportation, medicine, papermaking, energy, military industry, environmental protection and other industries, also known as "universal material". In order to meet the needs of this industry, especially wastewater treatment, and improve the efficiency of bentonite, it is necessary to modify bentonite. Here are some modification methods of bentonite.
　　Bentonite modification is generally divided into inorganic modification and organic modification. The commonly used modification methods of bentonite are activation modification, modification by adding modifier and sodium modification.
　　The activation modification method is to activate bentonite. The commonly used methods are acidification, roasting, salt activation, microwave activation, reduction, oxidation, etc., among which acidification and roasting are more commonly used. Acidification modification is that after acid treatment of bentonite, Na +, Mg2 +, K +, Ca2 + ions among bentonite layers can be dissolved into soluble salts, which weakens the bond between layers, increases the interlayer spacing, forms porous active substances with microporous grid structure and large specific surface area, and also removes impurities distributed in the structural channel of bentonite and increases its pore volume The diffusion of adsorbate molecules makes the modified bentonite have strong chemical activity and physical adsorption performance.
　　High temperature roasting method mainly caters to the different surface area of bentonite calcined at different temperatures. When the bentonite is heated, it will lose the surface water, adsorb the water and impurities in the pores, reduce the adsorption resistance caused by water film and impurities, and improve its adsorption property.
　　Modification by adding modifiers is a hot spot in this field, which can be divided into organic bentonite, cross-linked bentonite and organic cross-linked bentonite. Organic bentonite is a kind of bentonite prepared by modifying natural bentonite with organic modifier. The common organic modifier of bentonite is quaternary ammonium salt type cationic modifier. Its main mechanism is that the quaternary ammonium salt cation enters the interlayer of bentonite, which not only makes the interlayer distance of organic bentonite larger, but also improves its hydrophobicity, thus enhancing the ability of bentonite to remove organic matters. The cross-linked bentonite has adjustable pore size, uniform distribution and good adsorption. It can be used for the treatment of ionic or non-ionic pollutants in water.
　　The main methods of sodification of Ca bentonite include suspension method, dry mixing method, wet stacking method and wet extrusion method. Sodium carbonate and caustic soda are commonly used. The mechanism is that the cation calcium between montmorillonite layers is exchanged by ion exchange reaction, resulting in the loss of positive charge, which is balanced by the exchangeable cations adsorbed on the outer surface of the crystal and between the crystal layers.
　　In recent years, China has made some achievements in the modification of bentonite. At present, bentonite modified products have been applied to the treatment of organic wastewater containing aromatic compounds, printing and dyeing wastewater, petroleum wastewater, phosphorus wastewater and monosodium glutamate wastewater.