蒸汽闪爆处理对生姜纤维吸附性能的影响

生姜纤维来源于废弃的生姜渣,以生姜纤维资源化利用为前提,以制备一种高效处理染料废水的生物质吸附剂为目的,该文对生姜纤维进行蒸汽闪爆、冷冻粉碎联合处理得到闪爆粉碎生姜纤维吸附剂,探究了蒸汽闪爆处理及冷冻粉碎处理、不同吸附条件(吸附时间、pH值、盐浓度和蒸汽压强)对生姜纤维吸附性能的影响。结果表明:蒸汽压强为1.9 MPa时,闪爆粉碎生姜纤维对活性染料RB19的吸附量最高,其最大吸附量(115.12 mg/g)是原生姜纤维(48.80 mg/g)、粉碎生姜纤维(54.10 mg/g)的2.36倍、2.13倍,其吸附动力学过程符合准二阶动力学模型(R2为0.99),吸附等温线符合Langmuir模型(R2为0.99)。闪爆粉碎生姜纤维吸附能力经过吸附、解吸5次循环后仍保留80%,循环吸附性能良好。扫描电镜分析显示,随着蒸汽压强从1.3升高到1.9 MPa,生姜纤维内表面暴露出来,染料分子RB19更容易进入生姜纤维内部。X射线衍射(X-ray diffraction)分析显示,闪爆粉碎生姜纤维与生姜纤维相比,结晶指数从39%下降到20%,无定形区扩大,从而提高其吸附能力。研究结果可为生姜纤维用作染料废水吸附剂提供参考依据。

Effect of steam explosion on adsorption properties of ginger fiber

Ginger fiber(GF)is not suitable for textile due to its coarseness and it is usually disposed as wastes.This paper introduces a technology to make ginger fiber a valuable adsorbent of dyes in dyeing wastewater.The new technology is to explode the ginger fiber first by steam,and then frozen and disintegrate it to powder.We investigated the impact of a variety of factors in processing the ginger fiber on its ability to adsorb the dye RB19 in dyeing wastewater,which included the conditions under which the stream explosion was conducted,concentration of NaCl,and pH value.The surface morphologies and crystallization indexes of the ginger fiber before and after steam explosion were analyzed to elucidate the mechanisms underlying the improved adsorption of ginger fiber after steam explosion.Experimental results showed that steam explosion conducted under pressure1.9 MPa and lasting 150 s increased the adsorption from 48.80 to 115.12 mg/g.It was also found that several RB19 molecules aggregated to an ellipsoid with three axes:33.4?×11.4?×8.8?.Breaking the ginger fiber surface enhanced the movement of RB19 molecules into the exploded ginger fiber powder(EGFP)and steam explosion made EGFP much richer in GF than in crystal index(CI).Increasing the pressure under which the steam explosion was conducted from 1.3 to 1.9 MPa reduced CI in EGFP from 35%to 20%,indicated that the steam explosion opened the amorphous region in the ginger fiber and that the expansion increased with pressure.As such,it enhanced the adsorption of RB19.The increased adsorption was mainly due to the broken surface.In addition,EGFP became small particles with a diameter of 80μm,thereby enlarging the pores.Such structural changes made it easy for the dye molecules to move into the amorphous region of EGFP and improved its adsorption consequently.The steam explosion also increased the adsorbing rate,reducing the time required from the adsorption to reach equilibrium from 12 h to 8 h.The adsorption of RB 19 by the processed ginger fiber followed a second-order kinetic and the Langmuir thermodynamic model.After five cycles of adsorption-desorption,the adsorption capacity of the ginger fiber was still 80%of its original capacity.It is concluded that that steam explosion can effectively improve the adsorption capacity of ginger fiber.As a biomass adsorbent,EGFP can not only ameliorate the detrimental impact of dyeing wastewater on environmental but also turns a waste into a decontaminant amendment.It has potential applications in environmental engineering.