【作者】 王松；

【导师】 谢益民；

【作者基本信息】 山东轻工业学院 ， 制浆造纸工程， 2008， 硕士

【摘要】 仿酶催化不仅兼有酶催化与化学催化两者的优点,而且是实现绿色制浆化学的直接而有效的途径。本实验分别研究了GIF仿酶体系处理麦草CEL的机理,GIF仿酶体系预处理对麦草原料制浆性能的影响,Fe-CA仿酶体系联合活性污泥法处理制浆废水,在漆酶的作用下添加松柏醇去除废水中木素及其木素衍生物。以Cu²⁺/螯合剂/过氧化氢构成的GIF仿酶体系是模拟以Cu²⁺为氧化活性中心的漆酶的仿酶系统之一。本研究首先采用Cu²⁺/吡啶/过氧化氢的GIF仿酶体系对麦草的纤维素酶酶解木素（CEL）进行了仿酶降解,通过FT-IR以及GC-MS分析,解析了CEL在降解过程中的结构变化,并对CEL的仿酶降解机理进行了初步探讨。研究结果表明:该仿酶降解方法对CEL有较强的降解能力,酶解木素在仿酶体系中存在侧链上及甲氧基C-H键的破坏、木素结构中Cα-Cβ连接键的断裂、苯环的开环等反应。采用GIF仿酶体系对麦草进行预处理,研究了仿酶处理麦草对制浆性能的影响。对仿酶处理前后的化学组成进行测定,深入探讨了仿酶预处理的机理,为仿酶制浆领域的应用提供新工艺。结果表明,采用仿酶预处理的最佳工艺条件为:仿酶络合物用量为3mmol/kg绝干麦草,H2O2用量定为31.5g/kg绝干麦草,处理温度为30℃,处理时间4h。经GIF仿酶系统预处理后,Klason木素含量、苯-醇抽出物和灰分含量均有不同程度的降低。经GIF仿酶体系预处理后综纤维素含量为75.12%,与未处理样相比升高了3.41个百分点,处理后Klason木素降低了3.37个百分点。苯醇抽出物的含量降低了0.98个百分点。研究结果表明该仿酶系统不仅对麦草中的木素有较强的降解作用,而且对麦草表面的蜡质、脂肪酸等也具有一定的降解作用。从电镜照片可看出,经GIF仿酶系统预处理后的麦草表面变得粗糙不平,还有许多孔洞和凹坑,有明显纤维骨架露出,说明了GIF仿酶体系确实可以高效的脱除部分木素。天然纹孔和仿酶预处理产生的孔洞,可以降低后续药液渗透的阻力,为化学药液的渗透和木素的溶出提供更多的通道,从而改善了化学处理的效果。实验中产生的废水首先进行酸析处理以除去其中的大部分木素,随后采用铁系仿酶体系对其进行处理。铁-羧酸（Fe-CA）和H2O2组成的仿木素过氧化物酶酶体系能使部分木素发生脱氢聚合,从而使木素分子量增大,亲水性降低,易絮凝而除去。铁与羧酸形成的螯合物性能稳定,价格低廉。采用仿酶-混凝法处理高CODCr的制浆废水,CODCr、SS等主要污染物的去除率分别可达55%、60%以上,通过木素的大量脱除有效地提高了废水的可生化性,为难降解废水的后续处理创造了条件。实验结果表明应用Fe-CA处理系统可以很好的处理木素含量较高的制浆造纸中段废水,其最佳条件为:Fe-CA用量10g/m³,双氧水用量150g/m³,硫酸铝的投加量为300g/ m³,APAM加入量为5g/m³,处理时间1h,沉降时间3个小时。该处理工艺设备简单,操作方便,成本低,可以适应较高的废水负荷。经仿酶-混凝法处理后的废水在经过生化处理,既可达标排放。生化处理后的废水具有较高的色度,我们利用漆酶对木素的氧化催化作用,添加松柏醇使之与废水中的可溶性木素及其衍生物发生聚合反应,从而生成疏水性的大分子聚合物而溶出,可以实现造纸废水的深度处理。本实验选取松柏醇用量,漆酶用量,反应温度和反应时间来作为对处理后废水CODCr和色度的影响因素,设计正交实验,通过对实验结果的处理与分析而得到理论上的最佳方案,并通过验证试验得到最佳处理方案。实验表明,在漆酶的作用下添加松柏醇可以有效地去除废水中的可溶性木素及其衍生物,在松柏醇用量为0.078g/L,漆酶用量为14.72IU/L,处理温度为25℃,和处理时间为1h的条件废水的处理效果最好,此时,CODCr的去除率为68.1%,色度去除率为69%,木素的脱除率可达81%。更多还原

【Abstract】 Biomimetic catalyst has characteristics of both enzymatic catalyst and chemical catalyst. Therefore, it is an efficient approach of green chemistry in pulping. In this paper, the influence of wheat straw pulping properties on the pretreatment by GIF biomimetic system was investigated in detail. The treatment of effluent by Fe-CA biomimetic system combined with activated sludge process was also studied. After Fe-CA biomimetic treatment the lignin and its derivatives in the effluent were removed by dehydrogenation copolymerization with coniferyl alcohol catalized by laccase throughGIF system which is composed of Copper（II）/Pyridine/Hydrogen peroxide is one of the most promising biomimetic system. The GIF system simulates the function of laccase whose active center of oxidation is coordinated copper cation. In this research, cellulolytic enzyme lignin （CEL） of wheat straw was treated by the GIF system. Infrared spectra and GC-MS analysis were used to analyze the change of chemical structure of CEL after reaction. The mechanism of this biomimetic degradation process was discussed. The results showed that the degradation of CEL was very efficient with the copper（Ⅱ）/pyridine/peroxide system. According to structure of the products, it was proved that the following three types of reaction were caused by the GIF system: oxidative cleavage of C-H bond of the aromatic ring and side chain, Cα-Cβcleavage of lignin structural units, the opening of aromatic ring.Wheat straw was pretreated by GIF system in order to improve the efficiency of CMP pulping. The effects of biomimetic treatment on chemical composition and micromorphology of wheat straw were investigated. The results showed that the optimal condition of pretreatment was as follows:CuSO4 3mmol/kg wheat straw;H2O2 31.5g/kg wheat straw; Temp. 30℃; Reaction time 4h. The results showed that contents of Klasson lignin, ash and alcohol-benzene extractives decreased after the treatment. The content of Klasson lignin decrease from from 17.4% to 14.0% after the treatment..When the charge of CuSO4 and H2O2 increased, the content of Klason lignin decline rapidly at first stage. Then the change became slow. However, holocellulose content increased from 71.7% to 75.1% by GIF treatment.. Through analysis of SEM image, it was known that the surface of treated wheat straw became rough and porous.Some fiber framework could also be observed. It was suggested that biomimetic treatment not only removed a part of lignin efficiently, but also degraded wax and fatty acid on the surface of wheat straw. The pores could provide more channels and reduce the resistance of penetration of chemicals in the consequent CMP pulping. The biomimetic degradation was proved to be an effective pretreatment method for CMP pulping of wheat straw.Most of the lignin in effluent was removed by acidification. Theneffluent from papermill was treated by Fe-based biomimetic condensation combined with coagulation in this thesis. A stable and high efficiency Fe²⁺-carboxyl acid complexes （Fe-CA） which could simulate the lignin peroxidase was applied to treat the papermill wastewater by rapid oxidation followed by flocculation treatment. In this research work, effluent from CMP process was treated by Fe-based biomimetic condensation and degradation followed by Al2（SO4）3-APAM flocculation. The removal ratio of pollutant substances such as CODCr, SS were over 55%, 60% respectively. Therefore, the biodegradability of the wastewater after treatment was also improved. The results proved that the operation of biomimetic treatment process was favorable for further bio-treatment of the effluent, because most lignin derivatives in the effluent were removed through condensation reaction followed by coagulation. The results showed that Fe-biomimetic system had marked effect on wastewater treatment form wheat straw CMP process. The optimal condition was as follow: Fe-CA 10g/m3, H2O2 150g/m3, Al2（SO4）3（18H2O） 300g/m3, APAM 5g/m3, reaction time 1hr and sedimentation 3hrs. The process is characterized by simple equipment, easy control, low operation cost and enduring high pollution load. The final wastewater can reach discharge standards after biochemical treatment.The effluent after biochemical treatment was characterized by higher colourity. Laccase is a kind of powerful enzyme that is promising in pulping and papermaking industry. Because it can catalyze the polymerization and oxidative degradation of lignin. It has been proved that soluble lignin and its derivatives could be degraded, or polymerized, and removed through treatment with laccase followed by coagulation. Its merit is mild reaction condition, many advantages in the requirements for reaction condition and related equipments. A novel wastewater treatment system which consists of laccase catalyzer and coniferyl alcohol was developed. When coniferyl alcohol was added, it was found to polymerize with water soluble lignin. Thus the system produced high molecule hydrophobic lignin polymers. The experiment showed that addition of coniferyl alcohol could remove soluble lignin and its derivatives in the wastewater effectively under the existence of laccase. The result also showed that the optiomal treatment condition was as follows: coniferyl alcohol dosage 0.0788g/L; laccase consumption 14.72IU/L; temperature 25℃; reaction time 1h. The removel ratios for lignin reached 81%. CODCr removal reached 68.1%. The chroma was removed by 69%.更多还原