酸析-絮凝法处理造纸黑液

针对中小型纸厂经济状况、污水处理规模等特点,提出了酸析-絮凝法处理造纸黑液的工艺,确定了最佳工艺条件,并进行了工程分析。结果表明:酸析-絮凝处理造纸黑液其最佳条件为:pH值2.5;温度常温;沉淀时间30 min;96%~98%的H2SO4加入量为0.004 t/m3。絮凝用PAM的最佳条件为:pH值3.0~4.0,搅拌时间为20 min,澄清时间40 min,COD去除率为50%~60%,加入量为3.0 g/m3。     

快速消解分光光度法测定污水COD的应用

化学需氧量(COD)是评价水体有机污染程度的一项重要指标,是水质检测中必不可少的项目。相比经典的重铬酸钾法,快速消解分光光度法可以大批量检测COD浓度,操作非常方便;在165℃下消解反应仅需20min,分析时间大大缩短;重复性和再现性的相对标准偏差均小于2%,精密度较高;加标回收率为95.5%~101.3%,准确度较高。     

高浊度快速消解分光光度法测定CODcr方法改进

通过实验室的现有仪器,对高浊度快速消解分光光度法下CODcr方法的改进验证。应用连华科技5B-3C型COD快速测定仪改进后的方法与改进前进行对比并以传统回流容量法做参照。使用多次对比,离心条件改进后的方法在准确率、精密度以及加标回收率上都符合实验要求。改进后该方法虽然增加了一个步骤,但相对于回流容量法还是相对简单的,数据也更可靠准确性高,改进后的方法可应用于平时实验室水质中高浊度的CODcr的测定。     

烘箱快速消解-分光光度法测定制浆废水中的COD

介绍了用烘箱消解测定废水COD,烘箱消解分光光度法测定COD代替玻璃仪器回流消解测定COD,通过对两种消解分析样品测定的COD数据比较,结果表明烘箱消解法测定COD较国准法操作简便,速度快,并且检测数据同样准确可靠,完全能够用于实际检测工作中。     

造纸黑液制取木质素磺酸盐研究

以造纸黑液为原料,从中提取木质素,在NaSO3与木质素的质量比为3∶4,反应时间4h,工作压力0.6MPa的最佳条件下,经磺化成木质素磺酸盐。开发的产品可作沥青乳化剂、絮凝剂等。此法不仅提供了一种减少造纸污水对环境污染的方法,而且表明造纸污水的回收利用在工业、建筑业上有一定的利用价值,应用前景广阔。     

造纸黑液木质素及其综合利用

木质素是结构复杂的数量上仅次于纤维素的芳香族天然高分子物质,是人们提取和利用纤维素时的副产品,本文主要对国内近几年来有关木质素特别是造纸黑液木质素的综合治理和应用技术研究成果进行了综述,内容包括木质素化学结构及其在农林业、石油工业、混凝土工业、高分子材料和合成低分子化学品等领域的综合利用.     

酸析法提取芦苇纸浆黑液中的木质素

以碱法芦苇纸浆黑液为原料,研究了酸析法提取木质素的工艺.考察了酸析终点pH值、温度、保温絮凝时间对木质素回收量的影响.得出最佳条件是:pH值为3.0左右,温度为50 ℃,保温絮凝时间为30 min.在上述条件下,木质素的回收效果最佳.     

造纸黑液木质素资源化处理

造纸制浆废液回收的木质素具有多种活性基团,在土壤中能缓慢降解,适于配制缓释肥料。本文简要概述木质素在肥料领域中的技术研究与应用,内容主要包括木质素的化学特性,木质素氮肥、磷肥、多元复合肥和螯合微肥的研究应用。木质素肥料具有优越的特性和广阔的应用前景,加强其研究和应用,对促进木质素资源的充分利用与农业经济的持续发展和保护生态环境具有重要意义。     

烘箱消解—分光光度法测定地表水中有机磷

以烘箱代替压力蒸汽消毒器进行消解,采用过硫酸钾氧化—钼酸铵分光光度法测定地表水中的有机磷.实验结果表明,该法可简化消解过程,使温度易于控制,提高了有机磷测定方法的稳定性,同时该方法易于操作,其准确度、精密度、检出限等均令人满意.     

对制浆废液脱磺以提取木质素

以亚硫酸盐法制浆废液为原料,经脱磺处理后木质素的提取率显著提高,并通过(53)正交实验深入探讨经脱磺处理的黑液中硫酸用量、沉淀时间、沉淀温度等反应条件对木质素提取纯化的影响,得到高纯木质素提取纯化最佳条件为:黑液与15%硫酸体积比为1∶2,沉淀温度90℃,沉淀时间1.5 h。红外光谱、凝胶色谱、差热和流变特性分析结果表明,脱磺处理的木质素具有纯度高、分子量大、热稳定性和塑化性好等特点。     

紫外-可见光谱法测定黑液中木素含量

通过对3,5-二硝基水杨酸(DNS)及草浆黑液木素溶液紫外-可见特定波长区域光谱图的研究,建立了一种快速、简便、准确的草浆黑液中木素含量测定方法。研究结果表明,草浆黑液木素在520nm处DNS溶液吸光度值与木素溶解量二者具有较高的线性关系。该方法在测量时可以排除草浆黑液中还原糖及亚硫酸钠的干扰。不但能测定碱法草浆黑液中木素含量,还可以测定碱性亚硫酸盐法草浆黑液中木素含量。采用该方法测定草浆黑液中木素相对含量是准确可靠的。     

Process performance in lignin separation from softwood black liquor by membrane filtration

Black liquor is a side-stream in the production of kraft pulp. The extraction of lignin and hemicelluloses from black liquor would reduce the load on the recovery boiler and give valuable by-products. Lignin was separated from black liquor by membrane filtration, using one ceramic and three polymeric nanofiltration membranes, with molecular weight cut-offs in the range of 200 Da to 1 kDa. Ultrafiltration was tested as a form of pretreatment prior to nanofiltration to separate hemicelluloses from lignin. The use of ultrafiltration prior to nanofiltration increased the flux drastically in the nanofiltration step with three of the membranes. The ceramic membrane exhibited a higher flux and lower lignin retention than the polymeric membranes. The two membranes with a molecular weight cut-off of 1 kDa were found to have the best performance in parametric studies, and were therefore used in concentration studies. The results were used for a preliminary economic evaluation of the process. These calculations showed that the most cost-effective alternative for the extraction of lignin was with the polymeric 1 kDa membrane without pretreatment, and that the production cost for a lignin solution with a concentration of 230 g L⁻¹ would be 46 € per ton of lignin.     

Synthesis and characterisation of polyurethanes derived from waste black liquor lignin

Waste black liquor lignin, obtained from bagasse from the small-scale paper industry, can be utilized for the synthesis of polyurethanes (PUs). Several polyurethane samples were prepared from laboratory black liquor (LBL) by reacting varying amounts of lignin ranging from 5 to 70% (w/v) in poly(ethylene glycol) (PEG) (having molecular weights of 200, 600, 1000, 1500 and 4000) with tolylene 2,4-diisocyanate (TDI). The effects of lignin concentration and molecular weight of PEG on mechanical and thermal properties of PUs obtained were investigated. The polyurethanes synthesised were characterized for different properties such as shear strength, adhesion and thermal stability. The shear strength of PU joints with aluminum was found to decrease with increase in both lignin concentration and molecular weight of PEG. Maximum shear strength, i.e. 3.6 N/mm², was shown by 50% (w/v) lignin in PEG of molecular weight 200.     

蔗渣碱法造纸黑液回收木质素的结构及其燃烧特性

以酸析法从蔗渣碱法造纸黑液中回收蔗渣木质素（BL）,通过红外光谱（FTIR）,核磁共振氢谱（¹H NMR）和凝胶渗透色谱（GPC）对其进行了表征。结果表明,BL主要由愈创木基丙烷单元（G）和紫丁香基丙烷单元（S）通过C-O、C-C键合方式连接而成,其分子量分布较宽,分子之间存在较大差异。通过热重分析法（TG）研究了BL的燃烧特性,结果表明BL的燃烧主要发生在300~500℃的阶段,在此过程中BL分子中的C-C键发生断裂形成挥发分和焦炭,并迅速燃烧,失重率超过80%。通过扫描电子显微镜（SEM）和X射线荧光光谱（XRF）研究了BL在300、600、900和1100℃燃烧灰渣（BLR）的微观形貌和元素组成,结果表明BL呈结实、饱满的颗粒状,而BLR则表现为多孔的疏松堆积体或规则的片状结晶颗粒。随着燃烧温度的升高,BLR中的Na和K质量分数逐渐减少,而其他元素质量分数变化不大。     

Fractionation and concentration of kraft black liquor lignin with ultrafiltration

Kraft black liquor lignin is a biofuel that is separated from the cellulose during kraft pulping. Improved technology and energy integration in paper mills have led to an energy surplus at many mills. It is therefore of great interest to extract the lignin from the pulp mill and sell it as fuel to replace fossil fuel in other furnaces. The fractionation of kraft black liquor with a total dry matter content of about 15 wt% has been studied using ultrafiltration. The flux for three polymeric membranes with different cut-offs was investigated as well as their retention of lignin and other process specific substances. The retention of lignin for the three membranes with cut-offs of 4,8 and 20 kDa was 80%, 67% and 45%, respectively. The retention of sulphur and sodium was zero for all three membranes. The purity of the final lignin fuel is of importances as the ash content preferably should be as low as possible. The flux and retention during concentration and diafiltration of the black liquor were therefore studied. The dialfiltration operation was conducted in batch and semicontinuous mode. The lignin purity was 36% in the original kraft black liquor and 78% after semi-continuous dialfiltration.     

The pyrolysis of extracted solids from oxidized kraft black liquor after lignin precipitation

A laboratory investigation of the possibilities for the reduction of odor from Kraft mill stack gases by lignin precipitation from oxidized Kraft black liquor and subsequent pyrolysis of the filtrate solids has been carried out. Samples of oxidized black liquor were acidified with sulphuric acid and the lignin precipitate extracted. The extraction scheme indicates that > 90% w/w of the sodium in the original black liquor samples can be retained in the filtrate after lignin removal at final pH 2.0. The evaporated filtrate solids containing the bulk of the black liquor inorganic chemicals were pyrolyzed and the evolved hydrogen sulphide, methyl mercaptan and dimethyl sulphide monitored by gas-chromatography. Gas-chromatograph traces displaying the increase and decrease of methyl mercaptant evolution levels on pyrolysis of the filtrate solids to increasing temperatures are shown. A thermogravimetric technique was used to investigate the decomposition rates of the extracted samples and these rates correlated with the levels of sulphur gases evolved on pyrolysis. Heats of combustion were determined by bomb calorimetry. Sulphur losses from the filtrate solids and the Kraft black liquor total solids are compared. The results show a significant decrease in the evolution of organo sulphur gases from samples of ligninextracted black liquor solids in comparison with original total solids samples, an increase in the level of hydrogen sulphide evolution however, presents a problem.     

草浆造纸黑液用于人造板胶粘剂的研究

用造纸黑液、酸析后的木质素为原料制取了不同固含量的木质素酚醛树脂，采用热压机在1．2MPa压力、热压时间5min、温度140℃进行固化成型，分别测试了直接采用黑液和采用酸析后的木质素制成胶粘剂的剪切强度，并分析了苯酚取代量与剪切强度的关系。     

An eco-friendly and efficient route of lignin extraction from black liquor and a lignin-based copolyester synthesis

Traditional method for extraction of lignin from black liquor in chemical pulping processes requires a huge amount of toxic inorganic acids like sulfuric acid which are potentially harmful to our environment and life. Furthermore, the traditional method always contains multiple steps, and thus it is time-consuming process. With a purpose to eliminate all these above disadvantages, in this study, we successfully developed an efficient process for the extraction of lignin from black liquor using a non-toxic aluminum potassium sulfate dodecahydrate (AlK(SO₄)₂·12H₂O). The developed process is simple, efficient, and short-time, which obviously have more advantages over the traditional extraction method. Furthermore, the lignin extracted in this study was used to synthesize a copolyester through polyesterification between lignin and sebacoyl chloride. The copolymer possesses a molecular weight of 31,800, corresponding to four to five repeating units of lignin macromonomers. Notably, it showed a good thermal stability up to 200 °C in TGA analysis. It was also possible to shape the copolymer using solvent casting. We believe that this newly developed method of lignin extraction may exploit new applications for eco-friendly sustainable materials in various fields.     

从造纸黑液中提取木质素制备工业水处理剂M-03

以造纸黑液为原料,用絮凝—酸析联用技术从中提取木质素,对木质素磺化改性处理后,加入有机磷、锌盐和苯并三唑等与其复配,制备工业水处理药剂M-03。探讨了主原料配比、药剂用量、反应温度、反应时间等对药剂处理性能的影响,得出最佳复配条件:m(改性木质素)∶m(有机磷)∶m(氯化锌)∶m(苯并三唑)∶m(水)∶m(乙醇)=10 3∶0∶15∶2 4∶0∶3、反应时间2 h、反应温度(70±2)℃。并用静态实验法评价了M-03药剂的缓蚀阻垢性能,结果表明,该药剂缓蚀阻垢性能优良。