Modification Of Bentonite And Its Application As Textile Auxiliary

The development of society and the flourish of economy acceleratethe progress of dyeing and printing enterprises. At the same time, theybring also tremendous pressure to environment and resource, and makedyeing and printing industries facing new challenges. In our country, thewhole of waste water which is discharged from dyeing and printingindustries is about tenth of which is discharged from all industries, and ithas some characters such as abundance, plentiful organic contamination,heavy color, and changeful water quality. Today, environment protection isbecoming more and more important, so developing of all kinds of newtype of environment-friendly textile auxiliaries is one of effectivemeasures for reducing environment pollution in dyeing and printingindustries. Bentonite, a natural inorganic mineral, has many excellenttraits, and it is abundant in our country, inexpensive andenvironment-friendly. Accordingly, bentonite will be better future in thecourse of developing and applying new environment-friendly textileauxiliaries.In this paper, the modification conditions of natural Ca-bentonite are discussed. Then satisfying effects are achieved by applying respectively different modified bentonite as a pretreatment agent of cotton textile and a detergent in reactive cotton dyeing.Firstly, the process of activating bentonite is investigated. Optimal activating conditions, which include acidity, activating time, liquid-solid ratio and activating temperature are obtained by measuring activity degree and decoloration rate of activated clay to direct blue RL.Secondly, the activated bentonite is applied as pretreatment auxiliary agent of cotton textile. It can absorb heavy metal ion in the solution consisted of caustic soda and hydrogen peroxide and improve the stability of hydrogen peroxide for one-bath process. At the same time, it can also avoid rust stain on textile and enhance the whiteness of textile. The experimental results indicate that the pretreatment effects with activated bentonite as pretreatment auxiliary agent are equivalent with that pretreatment agent, which apply mineral as raw material in domestic market. So, H2O2 stabilization agent need no more be added in one-bath pretreatment process with activated bentonite as pretreatment auxiliary agent.However, the experimental results show poor performance of activated bentonite to absorb the reactive dyes, and it cannot be applied as a detergent in reactive cotton dyeing directly. In order to solve thisproblem, activated bentonite is modified with cationic surfactants. The optimum deterging conditions are determined by researching the effects of temperature, time and dosage of modified bentonite on the absoiptive capability to reactive dyes. The experimental results prove the washing fastness of reactive cotton dyeing is quite good with an extremely low CODCr value of residual soaping liquid when using modified bentonite in washing process. Consequently, modified bentonite is beneficial to environment protection.Yao Yongli (Applied Chemistry) Supervised by Professor He Jinxin...