Superior Au-adsorption performance of aminothiourea-modified waste cellulosic biomass

氨基硫脲功能化PGMA及对金的吸附性能（英文）

Waste cellulosic biomass obtains various applications due to low-cost and eco-benign characteristics.A general strategy is proposed for waste cellulosic biomass to be modified with dialdehyde functional groups as intermediates through periodate partial oxidation.Finally,aminothiourea-modified waste cellulosic biomass can be prepared through Schiff reaction.Waste corn stalk,cotton and paper as typical precursors,were used to prepare cellulosic biomass,abbreviated as AT-S,AT-C and AT-P,respectively,and their adsorption behaviors of Au(III)from the hydrochloric acid medium were investigated.The pseudo-second kinetics equation as well as the Langmuir isotherm equation can be used to depict the adsorption process,and the maximum adsorption capacities of Au(III)are21.4,19.0and3.28mol/kg for AT-S,AT-C and AT-P at298K,respectively.The adsorption capacities of Au(III)on aminothiourea modified corn stalk(AT-S)is almost357times greater than that of raw corn stalk.To the best of our knowledge,AT-S has the highest adsorption capacity towards Au(III).AT-S also displays a superior separation selectivity towards Au(III)in the presence of Cu(II),Ni(II),Co(II),Pt(VI),Pd(II)and Rh(III).Furthermore,the characterization analysis of XRD,TG,SEM,TEM and FTIR confirms that AuCl4– has been reduced to elemental Au nanoparticles and deposit onto the surface of the biomass.It shows a prospect for waste corn stalk to be used to adsorb Au(III)from liquid phase and the possible fabrication of gold nanoparticles by a general adsorption process without any reductant.

纤维素基废弃生物质具有价格低廉和环境友好等优点,因而得到了广泛应用。本文提出了一种纤维素基废弃生物质功能化的通用制备方法,即先通过NaIO4选择性氧化将废弃生物质转化为含双醛基的平台中间体,然后利用醛基特定的Schiff base反应引入对金离子有优良配位能力的配基。以典型的废弃纤维素基生物质,如玉米秸秆(AT-S)、棉花(AT-C)和纸(AT-P)为原料制备了氨基硫脲修饰的吸附剂。AT-S、AT-C和AT-P在298 K下对Au(Ⅲ)的饱和吸附容量分别为21.4、19.0和3.28 mol/kg,Au(Ⅲ)吸附量与吸附剂中硫脲官能团的含量成正相关性。Au(Ⅲ)的吸附符合准二级动力学吸附模型和Langmuir等温吸附模型。AT-S对Au(Ⅲ)的吸附量是玉米秸秆的357倍,是目前文献中报道的有关Au(Ⅲ)吸附容量最高的吸附剂。AT-S对Au(Ⅲ)与其他金属如Cu(Ⅱ)、Ni(Ⅱ)、Co(Ⅱ)、Pt(Ⅵ)、Pd(Ⅱ)和Rh(Ⅲ)有着优良的分离选择性。采用XRD、TG、SEM、TEM和FTIR进行分析表征,结果表明吸附的AuCl+4~–被还原为Au0纳米颗粒并沉积在AT-S吸附剂表面。