Preparation Of Cellulose Betainate And Its Application In The Prevention And Treatment Of Dyeing Pollution Of Reactive Dyes

Dyeing and finishing industry is committed to solve the problem of color and salt pollution in reactive dyeing. Biomass materials are not only rich in nature, but also shows non-toxic and biodegradable features, so they play an important role in the prevention and treatment of reactive dyeing pollution. Two different forms of cellulose betainate with good biocompatibility were prepared through esterification reaction of the different states of the cellulose-microcrystalline cellulose and cotton fibers with betaine hydrochloride which was used as the cationic reagent. Both of the two cationic cellulose showed positive charge due to the introduction of betaine, so it had good adsorption properties for the anionic reactive dyes. The modified cellulose can be used as adsorbents to deal with the dyeing wastewater and the modified cotton fibers can reduce salt pollution and color contamination in the reactive dyeing. The problem of color and salt pollution in reactive dyeing could be solved from two aspects: the treatment and prevention of the dyeing pollution.A novel environmental-friendly cationic cellulose betainate was prepared with a clean one-step dry method by using microcrystalline cellulose as raw materials, betaine hydrochloride as cationic agent. The suitable reaction conditions were got:n(cellulose glucose units):n(betaine hydrochloride):n(dicyandiamide)=1:1:0.5, reaction at150℃for3h. Betaine hydrochloride reaction efficiency was81%, the degree of substitution (DS) of the cellulose betainate could reach0.81. The structure and surface morphology of microcrystalline cellulose (MCC), alkali treated cellulose and modified cellulose were characterized using XRD,SEM and FT-IR. FT-IR confirmed the ester groups and quaternary ammonium groups were attached to the cotton surface.Removal of hydrolyzed C.I. Reactive Red24,C.l. Reactive Red195and C.I. Reactive Blue19with the adsorbent was carried out, and the effects of the adsorbent dose, pH, time, initial dye concentration and NaCl concentration on the dye removal efficiency (R,%) were investigated. The adsorption behaviour of cellulose betainate fits to the Langmuir adsorption isotherm. Under this condition, the dye decolorization rates was above95%. The maximum adsorption capacity of hydrolyzed C.I. Reactive Red24,C.I. Reactive Red195and C.I. Reactive Blue19was93.5mg/g,117.65mg/g,277.78mg/g, respectively. Betaine hydrochloride was used as the cationic reagent in the padding-baking procedure of the cotton fiber. The effect of amount of the betaine hydrochloride and dicyandiamide, baking temperature and times on the cationic cotton fiber was investigated. The optimal conditions were as follows:dicyandimine8%(w/w) and betaine hydrochloride8%(w/w), baking the cotton fiber at120℃for5min. Betaine hydrochloride reaction efficiency was32.0%, the degree of substitution (DS) of the cellulose betainate could reach0.023. The structure and surface morphology of untreated and treated cotton fiber were characterized using XRD and FT-IR. FT-IR confirmed the ester groups and quaternary ammonium groups were attached to the cotton surface.The dyeing properties of3dyes (Reactive Red M-3BE. Reactive Brilliant Blue KN-R and Reactive Yellow M-3RE) on the pretreated cotton fiber by different dyeing process (dip-pad-steaming process, pad dyeing-steaming dyeing process and cold-batch dyeing procedure) were then investigated. The dyeing fixation, K/S and fastness properties (especially light fastness) value increased as compared to those untreated cotton fibers. In the padding-steaming process, the light fastness of Reactive Red M-3BE improved to5-6. In addition, the betaine hydrochloride had a good cycle performance.