【摘要】：生物煉制是利用農(nóng)業(yè)廢棄物、植物基淀粉和木質(zhì)纖維素材料為原料,生產(chǎn)各種化學(xué)品、燃料和生物基材料的工業(yè)過程。生物煉制過程可大大提高可再生植物基原料的應(yīng)用范圍,為化學(xué)和能源經(jīng)濟(jì)方面在綠色可持續(xù)發(fā)展道路上提供有效方式。玉米秸稈為生物質(zhì)原料,其玉米秸稈纖維素為多孔結(jié)構(gòu),因含有大量的羥基而具有良好的親水特性,可發(fā)生酯化、醚化、接枝共聚等反應(yīng)。通過化學(xué)改性,在其活潑羥基上引入大量的功能性基團(tuán),與廢水中的金屬離子發(fā)生作用,可作為重金屬污染的水處理吸附劑。本論文主要研究內(nèi)容包括利用廉價(jià)的玉米秸稈,對(duì)其進(jìn)行化學(xué)改性,得到改性玉米秸稈吸附劑,探討關(guān)鍵因素交聯(lián)劑投入量、反應(yīng)溫度、反應(yīng)時(shí)間對(duì)改性玉米秸稈在廢水中Cr6+吸附效率影響。通過Box-Behnken試驗(yàn)設(shè)計(jì)優(yōu)化改性玉米秸稈吸附劑工藝參數(shù)。在單因素實(shí)驗(yàn)基礎(chǔ)上,通過中心組合實(shí)驗(yàn)的到吸附劑的最佳制備工藝條件為交聯(lián)劑二乙烯三胺用量1.25mL、接枝反應(yīng)溫度101℃、接枝反應(yīng)時(shí)間2.15h。通過傅里葉變換紅外光譜(FT-IR)、比表面積分析(BET)和掃描電鏡(SEM)表征其結(jié)構(gòu)特征。改性玉米秸稈FT-IR表明,胺基(N-H)官能團(tuán)的伸縮振動(dòng)吸收峰強(qiáng)度較大,可能是由于接枝到玉米秸稈上的季胺基團(tuán)引起的。BET分析表明,改性玉米秸稈的比表面積相對(duì)增加,有助于吸附能力的增大。SEM分析表明,改性玉米秸稈表面明顯凹凸不平,吸附六價(jià)鉻后表面呈現(xiàn)更多的顆粒狀物質(zhì),說明改性玉米秸稈吸附作用可能主要通過接枝到表面的季胺活性基團(tuán)實(shí)現(xiàn)。改性玉米秸稈吸附劑對(duì)六價(jià)鉻進(jìn)行吸附研究,探討了關(guān)鍵因素交聯(lián)劑投入量、反應(yīng)溫度、反應(yīng)時(shí)間對(duì)改性玉米秸稈在廢水中Cr6+吸附效率影響。在改性玉米秸稈吸附劑用量為0.6g/L、pH為2、吸附溫度20℃、吸附平衡時(shí)間120min條件下,對(duì)廢水中Cr6+的吸附量為176.5mg/g,去除率為99.9%。玉米在全球被廣泛種植,其副產(chǎn)物秸稈資源豐富,經(jīng)過化學(xué)改性后在纖維結(jié)構(gòu)中引入特定功能基團(tuán),使得改性玉米秸稈對(duì)特定的重金屬離子具有高的選擇性與吸附容量,將成為生物基吸附材料的重要開發(fā)方向,為將來替代價(jià)格相對(duì)較貴的吸附材料活性炭、離子樹脂等奠定基礎(chǔ),為秸稈的高效利用提供了重要途徑。
[Abstract]:Biological refining is an industrial process that uses agricultural waste, plant-based starch and lignocellulose as raw materials to produce various chemicals, fuels and biomaterials. Biological refining process can greatly improve the application of renewable plant-based raw materials and provide an effective way for chemical and energy economy in the path of green sustainable development. Corn straw is a biomass raw material, its corn stalk cellulose is porous structure, because of a large number of hydroxyl groups have good hydrophilic properties, can take place esterification, etherification, graft copolymerization and so on. By chemical modification, a large number of functional groups were introduced into the active hydroxyl groups, which acted on metal ions in wastewater and could be used as adsorbents for heavy metal contaminated water treatment. The main contents of this paper include the chemical modification of corn straw by using cheap corn straw, the preparation of modified corn straw adsorbent, and the key factors, such as the amount of cross-linking agent, reaction temperature, etc. The effect of reaction time on the Cr6 adsorption efficiency of modified corn straw in wastewater. The process parameters of modified corn straw adsorbent were optimized by Box-Behnken test. On the basis of single factor experiment, the optimum preparation conditions of the adsorbent were as follows: dosage of crosslinking agent diethylenetriamine 1.25mL, grafting temperature 101 鈩，

本文編號(hào)：2305967