【作者】 彭丹；

【导师】 欧阳自远；

【作者基本信息】 华南理工大学 ， 环境科学， 2013， 博士

【摘要】 在石油的使用过程中通常会造成许多污染问题，污染途径包括生产冶炼、运输和使用过程中的各个环节。石油泄漏不仅造成能源的损失，而且也对环境生态造成不利影响。近年来，石油及石油产品的污染已经造为了严重的水污染问题，从而引起广泛的关注并成为研究热点。虽然一些先进的治理技术已被开发并引入含油废水处理中，如化学混凝、微滤和超滤，但是它们需要昂贵的启动资金和运营成本，这些弊端都抑制了这些技术的应用。因此，有必要开发有效的，经济的环境友好的技术来处理含油废水。近年来，木质纤维素材料已开始用于对含油污水的去除。它们的优点在于选择性地去除水中油类污染物、可生物降解性、成本相对较低，以及对环境的影响小。玉米是主要的经济作物之一，生产过程中会产生大量的副产品，如玉米芯、玉米叶和玉米秸秆，如何合理利用是一个非常重要的课题。使用玉米秸秆作为吸油剂用于溢油的回收最近受到重视。但考虑到玉米秸秆原材料的吸油能力相对较低，使用前应采取一些改性方法，以提高它的吸油量。本研究以玉米秸秆作为原料（raw corn stalks,简写为RCS），采用纤维素酶和木质纤维素降解菌生物改性技术，制备出不同的吸附剂。然后分别对它们的性质和吸附性能进行研究，阐述了酶改性和真菌改性制备溢油吸附剂的吸附机理，并采用吸附动力学和吸附等温线对吸附过程进行拟合。得到的研究结果如下：1.以玉米秸秆为原材料，选取产自黑曲霉的纤维素酶和纤维素酶R10为改性剂，制备高效水体溢油去除剂的最佳条件分别是：45°C，黑曲霉纤维素酶投加量为100U/g和酶反应时间为6小时改性条件下，制备出高效溢油吸附剂ACCS；50°C，纤维素酶R10投加量为100U/g和酶反应时间为4小时改性条件下，制备出高效溢油吸附剂RCCS。2.以玉米秸秆、玉米芯和木屑作为原材料，用黑曲霉和黄孢原毛平革菌进行改性，其最佳改性条件分别为：添加外加碳源体系中，黑曲霉在30°C、玉米秸秆与水比例为1:3时，改性6天，分别制备出ANCS、ANCC和ANWC；在小米麦麸培养体系中（比例为2:1），黄孢原毛平革菌在37°C，改性21天，分别制备出PCCS、PCCC和PCWC。对比纤维素降解菌和木质素降解菌对农业固体废弃物吸油量的影响可以看出，纤维素降解菌改性效果优于木质素降解菌，木质素有利于原油的吸附。3.从表征结果和组分分析改性机理，可以看出纤维素酶改性和木质纤维素降解真菌改性对纤维素结晶度、比表面积和纤维素木质素组成的改变，直接影响着吸附剂的吸油量。两种改性方法都能使玉米秸秆的纤维素结晶度降低、比表面积增大，纤维素酶和纤维素降解菌丝能穿入纤维素的结晶区，弱化糖苷键，破坏规则的致密平行结构，形成无定形结构，这样玉米秸秆的无定形区域扩大，有利于油分子的渗入，从而提高材料的吸油量，同时疏水性的木质素相对含量升高，亲水性的纤维素相对含量降低，这样使得材料的疏水性增加有利于秸秆在油水表面的吸油。4.研究了吸附过程中吸附剂投加量（0.1-0.5g）、初始油量（5-30g）和吸附时间的影响。当初始油量高、吸附剂投加量小时，它们的吸附能力最好，其中ACCS是最好的吸附剂。从吸附动力学和热力学的研究结果分析，ACCS、RCCS、ANCC、PCCC、ANWC和PCWC对原油的吸附更好的与Langmuir方程式符合，说明它们对原油吸附是单层吸附，而ANCS和PCCS对原油的吸附更好的符合Freundlich方程式，说明它们的吸附过程是发生在非匀质表面的多层吸附。所有改性材料都符合二级动力学方程，比较它们的吸附半平衡时间和初始吸附速率发现，ANCS都比其他吸附材料要高。5.纤维素酶和木质纤维素真菌改性农业固体废弃物对原油的主要吸附机理是：生物酶和真菌菌丝使得材料获得较大比表面积和较小结晶度而有利于物理吸附，同时改变纤维素、木质素组成比例，提高材料的毛细管作用力，有利于油分子的粘附。更多还原

【Abstract】 The usage of oil usually causes much pollution, and they may occur during variousstages of its production, transportation and utilization. Oil pollutants are not only a loss ofenergy but also an adverse effect on wildlife. Recently, oil spill has become one of the mostserious problems, so it causes widespread concern and research hotspot. Although someadvanced technologies have been developed and introduced into the oily water treatment,such as chemical coagulation, microfiltration and ultrafiltration, the expensive initial andoperating cost inhibit the application of these methods. So, it is necessary to develop aneffective, economical and green technology to deal with the oil pollutants in water. Recentyears, Cellulose-based organic materials have been started to be used for oil removal frompolluted water. They have the advantages of selective removal of oil over water,biodegradability, relatively low cost, and limited impact on the environment.Corn is one of the major economical crops all over the world, and it produce abundant ofbyproducts such as corncob, corn leave and corn stalk, so the importance of utilization of ithas been realized. The usage of corn stalk as an oil-sorbent in the recovery of spilled oils hasreceived attention recently. Considering the oil sorption capacity of raw corn stalk isrelatively low, some modification methods should be taken in order to producehigh-efficiency oil-sorbent.In this paper, raw corn stalks (RCS) were used as raw materials, and the choices ofbiotechnology based on the use of cellulase and solid-state fermentation bylignincellulosic-degrading fungi in modification process were taken. These materials wereanalyzed by characterization, and their adsorption isotherm and kinetics were evaluated inbatch experiments. The main results are as follows:1. Corn stalks were treated using two kinds of cellulase as modifier, which includecellulase from Aspergillus niger and cellulase R-10, so as to achieve new kinds of modifiedbiosorbent for oil removal from water (named ACCS and RCCS). After6h cellulasetreatment of corn stalk at an enzyme loading of100U/g under45°C, ACCS got high sorption capacity of oils. After4h cellulase R10treatment of corn stalk at an enzyme loading of100U/g under50°C, RCCS got high sorption capacity of oils.2. Corn atalks, corncob and oak wood were treated using Aspergillus niger andPhanerochaete chrysosporium, and the optimum modification conditions were as follows: ForAspergillus niger modification with additional carbon, at30℃, the initial solid-liquid ratiowas1:3, and modification time was6days, ANCS, ANCC and ANWC were prepared; ForPhanerochaete chrysosporium modification in millet and wheat bran system (ratio was2:1),at37℃, after modification time of21days, PCCS, PCCC and PCWC were prepared.Compared the modification of both fungi, the effect of Aspergillus niger was better thanPhanerochaete chrysosporium, and cellulase as modifier was better than Aspergillus niger.Lignin is favor for oil adsorption.3. The main modification mechanisms were conclused from characrerization results andlignocellulose analysis. Both of cellulase and fungi modification could transformation of thecellulose structure, and decrease the value of CrI, and increase BET areas. The main reasonfor modification can be attributed to the penetration of cellulase and hyphae into thecrystalline region of cellulose, weakening of the glycosidic bonds and formation ofamorphous structures. Meanwhile, they could increase relative amount of hydrophobic lignin,and reduce relative amount of hydrophilic cellulose, so that the improvement of hydrophobicwas benefit to oil adsorption in oil/water system.4. The effects of sorbent dose (0.1to0.5g), initial oil amount (5to30g), and thesorption time were also studied. When at high initial oil amount and in small dosage, thesorption capacities of all materials were better, and ACCS was the best sorbent. The sorptionprecesses of ACCS, RCCS, ANCC, ANWC, PCCC and PCWC fitted for Langmuir sorptionisotherm, which means oil moleculors were adhered on their surface by single layer. Thesorption process of ANCS and PCCS was found to fit for Freundlich isotherm, which meanstheir sorption process takes place in a non-homogeneous surface of the multilayer adsorption,and they occurred physical sorption. All of these sorbents met the pseudo-second-orderkinetics, describing that the adsorption rate was relation with square driving force. Compared the half time of adsorption and initial adsorption rate, ANCS is the highest among thesesorbents.5. The main mechanism of adsorption of oil by cellulase and lignocellulose-degradingfungi modified corn stalks was physical adsorption depending on their larger surface, lowerdegree of crystallinity, and higher relative amount of lignin, leading to improve the adhesionto oil molecules by capillary force.更多还原