Study on fluidized-bed pyrolysis of waste paper

A lab-scale fluidized bed is setup and pyrolysis experiments are carried out. When temperature ranges from 400 to 700 ℃, the yields of solid residue, bio-oil and syngas range from 36% to 18%, 19% to 30% and 9% to 42%, respectively, and the mass balance of pyrolysis ranges from 80% to 95%. At 400 to 700 ℃, the characteristics of bio-oil are similar and the heat value is about 10 MJ/kg. When the temperature is over 600℃, the yield of syngas increases approximately twice as much as that at 500 ℃. The yields of CO2 and CO increase from 70 to 230 L/kg and 50 to 106 L/kg, respectively, while the yield of syngas only increases about 5% when the temperature increases from 600 to 700 ℃. The results indicate that the pyrolysis mechanism of waste paper is similar from 400 to 700 ℃, while the yield of syngas can be affected by secondary pyrolysis of bio-oil.

Effect of Waste Paper Fiber on Properties of Cementbased Mortar and Relative Mechanism

The aim of this work was to investigate the effect of waste paper fiber on the properties of cement-based mortar and the relative mechanism. The cement-based mortars with various contents and mixing way of waste paper fibers were prepared and the slump flow, setting time and strength developments of all mortars were tested. Besides, Ca（OH）_2 content in hardened pastes at different ages and the microstructures of all mortar at 90 d were observed by scanning electron microscopy. The experimental results showed that in the process of mixing, more superplastizier was consumed to maintain the workability because of the absorption of water and superplastizer on waste paper fiber. With more waste paper fiber being added, longer setting time is available for the pastes with it because of the carbohydrate dissolving and its retarding to the cement hydration. Waste paper fiber is adverse to the early and later strength of cement-based mortar, but it increases the mortar strengths at 7 and 28 d. The strength, Ca（OH）_2 content and microstructure are related to the content and mixing way of waste paper fiber. Waste paper fiber helps produce the Ca（OH）_2 at 7 and 28 d, but this case is reverse at ages of 1 and 3 d. Overall, waste paper fiber leads to the appearance of more pores in the hardened paste. However, it increases the toughness of cement-based mortar.

The Interaction Effects of the Parameters on Optimization Design in Paper Production Waste Usage on Alkali-Activated Slag with Taguchi Method

The paper investigates the second-order interactions of parameters in an alkali-activated mixture of paper production waste(PPW)and blast furnace slag(BFS)in Taguchi method.The PPW including lime mud(LM)and paper sludge(PS).This paper provides the experimental models to assess the compressive and flexural strength of them at 7-day and 28-day.The results have shown that the second-order interactions between PPW and alkali-activated activator exists in each experimental model,and the significant interactions affect the selection of optimal compositions.Compared with the interactions between the PPW themselves,the interactions between PPW and alkali-activated parameters are the main significant factors affecting its physical properties.In each experimental model,the maximum compressive strength was 47.41 MPa in 7-day and 65.64 MPa in 28-day.Compared with the confirmatory experiments,the deviation of prediction calculated by experimental models was 3.08%and 0.56%,respectively.The maximum flexural strength was 5.74 MPa in 7-day and 5.96 MPa in 28-day;compared with the confirmatory experiments,the deviation of prediction calculated by experimental models was 5.40%and 0.17%.Considering the influence of circular materials,30%of PPW should be a suitable ratio to replace BFS as the raw material of alkali-activated slag(AAS).

China＇s Sustainable Strategy on Waste Paper as Reusable Resources

Resource reuse and sustainability are gradually becoming hot issues nowadays. Waste paper is an important material in paper reproducing. Comparing to wood pulp, waste paper is more energy-saving and environmentally-friendly. Being a top of one paper producing country in the world, China needs a continuous large quantity of waste paper supply. Waste paper strategy＂ is being taken seriously until the ti^ding of paper manufacttlring period. This paper strives to examine the waste paper circle and the changes of waste paper resource strategy in China nowadays by doing both amount and price analysis on waste paper trade. It is found that China now strives to promote a sustainability of waste paper resource reuse by drawing down waste paper import, increasing domestic reuse and increasing import channels and categories.

Greener,Safer Packaging:Carbon Nanotubes/Gelatin-Enhanced Recycled Paper for Fire Retardation with DFT Calculations

Fire retardant CNTs/WPP/Gel composite papers were fabricated by incorporating bio-based carbon nanotubes(CNTs)recycled from mature beech pinewood sawdust(MB)and cellulosic waste printed paper(WPP)into a gelatin solution(Gel)and allowing the mixture to dry at room temperature.The CNTs within the WPP matrix formed a network,enhancing the mechanical and thermal properties of the resulting CNTs paper sheet.In comparison to pure WPP/Gel,CNTs/WPP/Gel exhibited superior flexibility,mechanical toughness,and notable flame retardancy characteristics.This study provides a unique and practical method for producing flame-retardant CNTs/WPP/Gel sheets,suitable for diverse industrial applications,especially packaging,where used paper materials pose a significant fire risk.Bio-CNT-based fire-resistant packaging offers enhanced safety during transportation and storage.The sheets demonstrated increased strength and stiffness,with optimal mechanical properties achieved at a 20%CNTs loading.Additionally,thermal stability was improved,as confirmed by thermogravimetric analysis(TGA)and differential thermogravimetry(DTG).Flame retardancy tests revealed a rise in LOI(Limiting Oxygen Index)values with increasing CNTs content,indicating the CNTs’effectiveness in inhibiting combustion.The compatibility of recycled paper,CNTs,and Gel suggests potential applications in industrial fields,capitalizing on the biocompatible and biodegradable nature of cellulose.Density functional theory(DFT)calculations using the B3LYP with the 6-31G(d)basis set were employed to optimize the stability of these compounds and elucidate their chemical interactions.

不同种类木质纤维形态特征与性能对比研究

通过对不同原料制备的典型木质纤维的形态特征与性能进行对比研究,分析了不同种类木质纤维的特点与性能存在差异的原因。研究结果表明:以废报纸为原料制备的木质纤维样品主要由机械针叶木纤维与化学阔叶木纤维组成,以书本纸为原料制备的木质纤维样品主要由化学机械阔叶木纤维与机械针叶木纤维组成,以木纹纸为原料制备的木质纤维样品主要由机械针叶木纤维与半化学阔叶木纤维组成。不同种类的木质纤维性能存在明显差异,以废报纸和书本纸为原料制备的木质纤维吸油性能强,以木纹纸为原料制备的木质纤维灰分含量最多,以棉为原料制备的木质纤维0.15 mm质量通过率最高。木质纤维的吸油率、灰分含量和0.15 mm质量通过率等指标容易出现问题,应加强相关质量管控。

Paper-derived cobalt and nitrogen co-doped carbon nanotube@porous carbon as a nonprecious metal electrocatalyst for the oxygen reduction reaction

The oxygen reduction reaction(ORR)is a vitally important process in fuel cells.The development of high‐performance and low‐cost ORR electrocatalysts with outstanding stability is essential for the commercialization of the electrochemical energy technology.Herein,we report a facile synthesis of cobalt(Co)and nitrogen(N)co‐doped carbon nanotube@porous carbon(Co/N/CNT@PC‐800)electrocatalyst through a one‐step pyrolysis of waste paper,dicyandiamide,and cobalt(II)acetylacetonate.The surface of the hierarchical porous carbon supported a large number of carbon nanotubes(CNTs),which were derived from dicyandiamide through the catalysis of Co.The addition of Co resulted in the formation of a hierarchical micro/mesoporous structure,which was beneficial for the exposure of active sites and rapid transportation of ORR‐relevant species(O2,H+,OH?,and H2O).The doped N and Co formed more active sites to enhance the ORR activity of the electrocatalyst.The Co/N/CNT@PC‐800 material exhibited optimal ORR performance with an onset potential of 0.005 V vs.Ag/AgCl and a half‐wave potential of?0.173 V vs.Ag/AgCl.Meanwhile,the electrocatalyst showed an excellent methanol tolerance and a long‐term operational durability than that of Pt/C,as well as a quasi‐four‐electron reaction pathway.The low‐cost and simple synthesis approach makes the Co/N/CNT@PC‐800 a prospective electrocatalyst for the ORR.Furthermore,this work provides an alternative approach for exploring the use of biomass‐derived electrocatalysts for renewable energy applications.

Treatment and Resource Utilization of Deinking Sludge from Regenerated Paper Mill

To fully utilize secondary resources,it will inevitably generate a large amount of deinking sludge using waste paper as raw material for paper making.The sludge contains small fibers and dissolved substances of various chemicals.After adding flocculant and settling treatment,deinked sludge is formed.However,its organic matter content can reach a high level of 40%to 50%,and it can also be reused,effectively avoiding the harmful impact of papermaking sludge on the environment.

WET STRENGTH PAPER REPULPING: LABORATORY EVALUATION

The recycling of wet strength papers in a normal recycling mill is often troublesome due to the severe operating conditions required to defibre wet strength papers. The various methods are presented which will quickly allow mills to determine the most effective pulping aids to use when repulping wet strength papers. The repulping of wet strength paper with inorganic chemicals was investigated in the laboratory. The effects of major variables, that is, repulping time, pulp consistency, soaking time, temperature, and reactant concentration in the repulping stage were examined using Plackett-Burman design. The repulping time was the most crucial & influential process variable affecting repulping characteristic and formation related properties. The more significant repulping process variables affecting pulp yield were repulping time, soaking temperature and pulp consistency whereas for formation index and feature size, repulping time, pulp consistency, soaking temperature and time were the more important variables. The formation index is increased by an increase in repulping time, pulp consistency and soaking time whereas the feature size is decreased by an increase in repulping time, soaking temperature and pulp consistency. The formation index and the rejects were more sensitive to changes in process variables than were the feature size or the pulp yield. The pulp recycled from wet strength waste paper had good physical strength properties.

废纸制浆造纸废水好氧生物强化增效处理研究

以竹炭为载体制备氮铈掺杂改性且固定化微生物及微量元素的生物增效材料,采用生物强化增效技术对废纸制浆造纸废水的好氧处理进行优化,通过降低生化处理出水浓度来降低深度处理的难度和成本。利用SEM和16S rRNA测序等手段对活性污泥表面形貌及结构和微生物菌落结构进行分析,综合评价了生物强化增效技术对废纸制浆废水好氧生物处理性能的影响。研究结果表明:该技术可以提高污染物生物降解能力,提高生物处理效果。普通生化处理出水COD平均值140 mg/L、氨氮平均值2.3 mg/L,色度平均值260倍,平均COD去除率86.47%、平均氨氮去除率88.83%、平均色度去除率33.33%;同等条件下,生物增效处理出水COD平均值72.2 mg/L、氨氮平均值0.95 mg/L、色度平均值50倍,平均COD去除率93.02%、平均氨氮去除率达到了95.39%、平均色度去除率87.18%,处理效果明显优于普通生化处理。生物增效处理出水采用传统PAC或PFS处理均可达到排放标准,且PFS的处理成本低至0.63元/m^(3);而普通生化处理只能采用芬顿处理才能达到排放标准,且处理成本达3.27元/m^(3)。SEM分析结果显示:生物增效处理的活性污泥絮体结构紧凑,具有更高的生物量;与普通生化处理的污泥相比,生物增效处理的污泥中脱硫杆菌门(Desulfobacterota)和拟杆菌门(Bacteroidota)丰度增加了3.07和2.29个百分点,unclassified_o_PB19属增加了2.96个百分点,说明生物增效材料的投加能帮助一些具备特殊降解功能的微生物创造有利生存环境并激活其生长,提高了反应体系的定向降解能力。

基于大数据视域下造纸工业废水控制软件系统升级改造研究

造纸业对水的需求整体较大,在造纸的过程中所生成的废水涉及到各类杂质,如颜料、纤维等,若是无法及时进行相应处理,则会对周围环境带来显著影响。基于大数据技术,成功开发造纸废水远程监控系统,对原有的废水控制系统进行升级。升级之后的系统使用微信小程序用作上位机,而下位机则使用了STM32芯片,借助于WIFI模块、云服务器等,将现场运行的动态参量传递至微信小程序,可对设备进行远程监控。系统在运行之后,具有较高的实时性,同时反应也具有较高的灵敏度,可以对造纸厂的废水排放进行远程监控。

中国纸和纸制品加工贸易发展现状及趋势分析

中国加入WTO之后,加工贸易成为中国纸和纸质品最重要的贸易方式。文中总结中国纸和纸制品加工贸易发展现状以及废纸禁令对中国纸和纸质品加工贸易的影响,认为在此背景下,中国纸和纸制品加工贸易仍将稳定发展、纸和纸制品加工贸易或将向进料加工倾斜,并据此提出以下建议:一是促进纸和纸制品加工贸易产品结构升级优化,二是持续深化纸和纸制品加工贸易产业向低梯度地区转移,三是拓宽纸和纸制品加工贸易市场范围。

微波加热下生活废纸和PE塑料共热解产气特性

以可燃生活垃圾中的主要成分——生活废纸和聚乙烯(polyethylene,PE)塑料为原料,采用微波加热,对纸张/PE共热解中产气释放过程、产气成分和产气率等特性的影响规律进行研究。实验结果表明:在600℃热解终温下,产气成分以CO、CO_(2)为主,约为35%~40%,其次为CH_(4)、H_(2),其他气体含量较低。随着微波功率的增加,热解产气各成分的产量都明显增加,且各产气析出温度及峰值温度向高温方向移动。随着物料中PE的混合比例增加,纸张/PE共热解产气率降低明显,焦油产率则明显增加,表明PE热解产物以焦油为主。在定热解终温的情况下,添加热解碳对热解产气成分的体积分数影响不大,但可有效提高热解产气量。

废纸纤维改性聚乳酸复合材料性能研究——以应用于运动鞋领域为例

聚乳酸纤维材料是一种兼具优异环保性和物理性能的新型复合材料。为探究聚乳酸纤维材料在运动鞋领域中的应用可行性,借助废纸纤维对一般聚乳酸纤维材料进行了改性,借助发泡机、注塑机、鞋底成型机等设备制备了一种废纸改性聚乳酸复合材料运动鞋鞋底,对该鞋底的综合性能进行试验分析。结果表明:与传统的运动鞋鞋底材料相比,废纸纤维改性聚乳酸复合材料鞋底在力学性能、环保性能等方面具有显著优势,在减震方面优势不明显。

废纸纤维聚乳酸复合材料的制备及性能研究——以应用于极简跑鞋加工领域为例

为解决现有聚乳酸复合材料应用于极简跑鞋加工领域时存在的韧性不足、脆性大等问题,借助废纸纤维对聚乳酸复合材料进行了共混加工,对影响废纸纤维聚乳酸复合材料性能的因素如废纸纤维的打浆时间及其掺量等进行分析。结果表明:当废纸纤维打浆时间为30min,废纸纤维掺量为25.0%时,废纸纤维改性后的聚乳酸复合材料拉伸强度、弯曲强度分别达到了24.3MPa、44.4MPa,与一般聚乳酸复合材料相比更适合应用于极简跑鞋等的加工环节。

基于垃圾循环利用的高校绿色生活方式构建研究

加快形成绿色生活方式是推动发展方式转型的重要举措。本文首先从顶层设计、实践进展和社会氛围方面分析了绿色生活方式构建现状,提出了深化领域认识、分步推进实施、支撑设施建设等努力方向。接着结合对高校组织有序、特点鲜明和新时代背景下文化传承等使命的论述,提出了以高校作为绿色生活方式构建点的必要性。以典型的纸质垃圾为例,从典型性分析、有效分类、精准回收、循环利用方面进行了绿色生活方式构建设想。

剪切增稠液增强高发泡率废纸缓冲材料的制备及性能

随着经济的快速增长和人们环保意识的不断增强,植物纤维类环保型发泡缓冲材料逐渐成为研究热点。为改善植物纤维发泡材料发泡率低、缓冲吸能效果差等问题,本研究设计半密闭型发泡模具,成功制备了具有高发泡率和优异吸能性的废纸缓冲材料并对制备工艺进行了优化。结果表明:使用质量分数为0.5%的氢氧化钠溶液预处理废纸浆,不仅可以有效去除废纸中的杂质,而且能在不降低纤维长度的情况下对废纸纤维进行适当改性,有利于提高废纸缓冲材料的发泡率和整体性能。以正交优化试验研究原料配比对废纸缓冲材料性能的影响,并据此确定了最优配方。通过设计全新半密闭型发泡模具,成功制备高发泡率的废纸缓冲材料,其膨胀率相较传统制备方式提高了3~4倍。本研究首次引入剪切增稠液(STF)增强废纸纤维,考察了STF含量对废纸缓冲材料力学性能、发泡倍率和回弹性能的影响,分析了STF对废纸缓冲材料的增强机理。结果表明:STF能够提高单根废纸纤维的强度并增强纤维之间的连结,从而提升缓冲材料吸能性,且随着STF含量的增加,材料的吸能性逐渐增强,发泡率逐渐降低,当STF含量为10%(质量分数,下同)时,STF增强废纸缓冲材料的综合性能达到最优。

高校废纸回收及再利用体验模式设计研究

目的 基于高校废纸产生及回收利用情况,结合当下生态美育的发展课题,旨在探索以废纸浆为材料的实践型生态美育路径。方法 在理论层面建立起高校生态教育、审美教育与纸浆艺术、手工实践之间的关联。通过问卷调查和文化探针洞悉用户的行为习惯和对废纸回收并艺术化利用的期望感知。建立用户旅程图,从而进一步明确废纸回收投放站点、线上小程序,以及纸浆手作材料包三大主要体验接触点。通过头脑风暴和Kano模型对功能设计点进行发散和筛选,并产出设计原则和策略。结论 通过“废止计划”体验系统建立起以废纸浆材料为联结的高校废纸回收及纸浆手作艺术实践的循环,从而实现高校废纸材料的趣味性再利用。构建以废纸浆为材料的生态美育实践模式,推动高校生态美育的特色化、普及性和可持续发展性。

超微孔废纸碳气凝胶的制备及其CO_(2)吸附性能研究

气候变化的加剧要求更加绿色高效的碳减排技术和产品的开发。固废和生物质衍生的常规CO_(2)碳质吸附剂材料吸附效果较差,需要进行额外的活化改性以提升多孔炭的吸附性能。本工作以废纸为原料,经过简单预处理和溶胶凝胶炭化工艺,得到微孔高度发达的超微孔废纸碳气凝胶,探究了不同种类废纸和制备温度的影响。对材料的理化特性和CO_(2)吸附性能进行了表征和测试,结果表明,废纸碳气凝胶的孔隙结构发达,呈类蜂窝状。打印纸为原料,800℃下制备的废纸碳气凝胶具有大比表面积1369.94 m^(2)/g、高孔容0.59 cm^(3)/g和孔径为0.4-0.8 nm的超微孔。无需改性,0℃时的CO_(2)吸附量为247 mg/g,对应CO_(2)/N_(2)吸附选择性为11,25℃时的动力学吸附量为151 mg/g,七次吸脱附循环的平均波动幅度小于5%,对烟气CO_(2)(10%)的捕获量为42 mg/g。废纸碳气凝胶展现出优异的CO_(2)吸附性能和再生稳定性,优于固废和生物质衍生的常规炭材料。本工作也为固废处置和资源化利用提供了新思路。