El Achaby M, Fayoud N, Figueroa-Espinoza M C, Ben Youcef H, Aboulkas A
Materials Science and Nanoengineering Department, Mohamed 6 Polytechnic University Lot 660 - Hay Moulay Rachid Benguerir 43150 Morocco
Montpellier SupAgro, UMR IATE Montpellier F-34060 France.
RSC Adv. 2018 Jan 31;8(10):5212-5224. doi: 10.1039/c7ra10239a. eCollection 2018 Jan 29.
Cocoa bean shells (CBS) are a by-product of the cocoa bean processing industry. They represent 12-20 wt% of dry cocoa beans, after having been separated from these by a roasting process. CBS often end up as a waste product which contains around 34 wt% of cellulose. The transformation of this waste into valuable and marketable products would help to improve waste disposal. Indeed, the large annual production of this waste makes it a sustainable and renewable bio-source for the production of chemicals and fibers for advanced applications. In this work, new cellulose microfibrils (CMFs) with a tendril helical morphology and highly hydrated gel-like behavior were successfully extracted from CBS waste using a controlled chemical extraction process. During this study, several physico-chemical characterizations were carried out in order to identify the properties of each of the products at different stages of treatment. Microscopic observations show that the extracted CMFs have a tendril helical shape like climbing plant tendrils. Due to this special morphology, the extracted CMFs show a highly hydrated state forming a gel network without additional modifications. The as-extracted CMFs were used as adsorbent material for the removal of methylene blue from concentrated aqueous solution, as an application to wastewater treatment for the removal of basic dyes. Swelling properties, adsorption kinetics and isotherms were carried out in batch experiments. The results indicated that the CMFs have a high swelling capacity (190%). The pseudo second order model can be effectively used to evaluate the adsorption kinetics and the adsorption isotherms can also be described well by the Langmuir isotherm model with a maximum adsorption capacity of 381.68 mg g. Thus, the as-extracted CMFs with unique characteristics have the potential to be used as efficient adsorbent material for the removal of different cationic dyes from industrial wastewater.
可可豆壳（CBS）是可可豆加工业的一种副产品。在通过烘焙过程与干可可豆分离后，它们占干可可豆重量的12 - 20%。CBS通常最终成为一种废品，其中含有约34%重量的纤维素。将这种废物转化为有价值且可销售的产品将有助于改善废物处理。事实上，这种废物的年产量巨大，使其成为用于生产高级应用化学品和纤维的可持续且可再生的生物源。在这项工作中，使用可控化学提取工艺成功地从CBS废物中提取出了具有卷须螺旋形态和高度水合凝胶状行为的新型纤维素微纤丝（CMF）。在这项研究中，进行了几次物理化学表征，以确定处理不同阶段每种产品的特性。显微镜观察表明，提取的CMF具有像攀缘植物卷须一样的卷须螺旋形状。由于这种特殊形态，提取的CMF呈现出高度水合状态，形成凝胶网络而无需额外改性。提取的CMF被用作吸附材料，用于从浓水溶液中去除亚甲基蓝，作为去除碱性染料的废水处理应用。在分批实验中进行了溶胀性能、吸附动力学和等温线研究。结果表明，CMF具有高溶胀能力（190%）。伪二级模型可有效用于评估吸附动力学，吸附等温线也可以用朗缪尔等温线模型很好地描述，最大吸附容量为381.68 mg/g。因此，具有独特特性的提取CMF有潜力用作从工业废水中去除不同阳离子染料的高效吸附材料。
