废玻璃钢粉填充丁腈橡胶的性能研究

研究了废玻璃钢粉填充丁腈橡胶的性能。从取向和非取向两个方面探讨了废玻璃铜粉含量对丁腈橡胶性能的影响,比较了废玻璃铜粉和碳酸钙对丁腈橡胶性能的影响。结果表明,玻璃钢粉对于丁腈橡胶具有一定的补强作用,随着玻璃钢粉加入量的增加,电阻率略有下降;由于玻璃短纤维的存在使得胶片取向与非取向方向的性能有所差异。综合性能考虑,使用20份废玻璃钢粉的复合材料具有较高的性能价格比。     

C20全废混凝土再生骨料透水混凝土配比试验

为了再利用建筑垃圾,节约天然骨料资源,试验骨料全部采用废混凝土,研究水灰比、胶骨比及减水剂对废混凝土再生骨料透水混凝土性能的影响。结果表明:在胶骨比不变时,水灰比增加,抗压强度增加、孔隙率降低;在水灰比不变时,胶骨比增加,抗压强度增加、孔隙率降低;减水剂可以改善拌合物的和易性,从而提高抗压强度,降低孔隙率,但加入量不宜过大;用全废混凝土完全可配制出符合规范要求的透水混凝土。     

铸造废砂/废地膜/粘附土三元复合体系的研究

通过X射线衍射分析、红外光谱分析、热分析、电镜及能谱分析、图像分析,可以判断废旧地膜上粘附土的主要矿物质是结晶二氧化硅（粉粒级石英）,它们与聚合物基废弃物复合材料中作为填料的铸造石英砂的性状类同。废旧地膜可以不经清洗,直接与铸造废砂制备复合材料,这可大大降低复合材料的加工成本。这种复合材料实际上是由基体PE、粘附土中大量的SiO2和铸造石英砂SiO2组成的三元复合体系。     

利用含铝废硫酸和废铝渣制备聚合硫酸铝

以含铝废硫酸和废铝渣为原料制备聚合硫酸铝（PAS）。优化了废铝渣的酸溶条件,确定了合适的稳定剂和碱化剂。实验结果表明：在酸溶反应温度为80 ℃、酸溶反应时间为40 min、以20 g/L Ca（OH）₂溶液为碱化剂、以加入量为60 mg/L的固体柠檬酸为稳定剂的条件下,制备的PAS比聚合氯化铝（PAC）和Al₂（SO₄）₃具有更优异的混凝性能。该工艺可回收利用废铝渣和含铝废硫酸,从而达到综合利用的目的。     

废再生纸纤维厌氧发酵生物制氢

采用稀硫酸预处理废再生纸厌氧发酵生物制氢。在稀硫酸质量分数为0.5%、废再生纸粒径为0.350mm、反应温度为115℃、反应时间为60min、固液比(废再生纸质量与稀硫酸体积的比,g/mL)为1∶16的最佳废纸预处理条件下,还原糖得率高达56.28%。产气量随发酵时间延长而增加。在10d的发酵时间内,废再生纸一次性加入20g的A组于发酵3h后开始产气,总产气量为2 593.3mL,产氢率为42.8mL/g;废再生纸加入量为2g/d的B组于发酵9h后开始产气,总产气量为2 759.4mL,产氢率为36.4mL/g。随发酵时间延长,A组和B组的pH均呈下降趋势;A组的挥发性脂肪酸含量(VFA)快速增加,发酵144h时VFA达到最大,为1 224mg/L,而B组的VFA增加速率较慢,发酵168h时达到最大,为1 135mg/L。     

废粘土砖粉潜在活性探究

通过将磨细的废砖粉取代水泥制作胶砂试件,并测其抗折、抗压强度值来研究废砖粉的潜在活性,并在此基础上,进一步研究了石灰对废砖粉活性的激发作用.结果表明：磨细的废砖粉具有潜在活性,且粒径越小,活性越大;在一定掺量时,石灰可进一步激发废砖粉的活性.     

利用含铝废盐酸制备聚合氯化铝

以某医药企业产生的含铝废盐酸为原料制备了液体聚合氯化铝(PAC)。确定了适宜的有机物去除方法和碱化剂,考察了碱化剂投加量、废盐酸铝离子含量等合成条件对PAC产品指标的影响,并比较了自制PAC和市售PAC对该企业污水站二沉池出水的混凝效果。实验结果表明:采用活性炭吸附法去除废盐酸中有机物,选择固体Ca O作为碱化剂,在活性炭投加量1‰(w)、吸附时间1 h、铝离子含量9.5%(w,以Al_2O_3计)、CaO投加量80 g/L、反应时间24 h的条件下,制备的液体PAC达到行业标准HG/T 2677—2017《工业聚氯化铝》中的Ⅲ类标准;自制PAC对废水COD和SS的去除率均优于市售PAC,不仅可替代其使用,还可外售产生经济效益。     

用废砖制作利废型轻质墙体材料试验研究

采用正交试验的方法,研究了废砖、废聚苯粒及天然砂的不同配比对利废型轻质墙材性能的影响,配制出了抗压强度5.0 MPa以上,表观密度1 100 kg/m3以下,导热系数0.2 W(/m.K)以下,50次冻循环强度损失率20%以下,质量损失率5%以下的利废型轻质墙材,并讨论了骨料的不同配比与性能的关系。     

工业废催化剂的回收利用与环境保护

大量工业废催化剂的丢弃,不仅是一种资源的浪费,而且对环境也会造成一定程度的污染,针对工业废催化剂的回收利用进行了探讨,着重介绍了几种工业废催化剂的综合回收技术.     

乙烯废碱液的再生

开发了除油-苛化-脱硫组合技术处理乙烯废碱液工艺,考察了影响各级处理效果的主要因素.实验结果表明:经石英砂-聚丙烯腈纤维膜-强碱性阴离子交换树脂组合装置除油后,碱液中油类物质质量浓度小于2 mg/L,NaOH,Na_2CO_3,Na_2S等无机组分含量基本不变;经苛化-脱硫处理后碱液中Na_2CO_3和Na_2S质量浓度分别小于4 430 mg/L和4 480 mg/L;再生碱液的流体力学性质及对酸性气体的吸收性能均可满足乙烯裂解气碱洗要求.     

Novel polyol initiator from polyurethane recycling residue

Flexible polyurethane foams can be advantageously treated by two-phase glycolysis in order to recover polyols with improved quality. The bottom phase obtained, which contains highly toxic reaction by-products and the excess glycol, presents an environmental and economic problem which should be solved. The main purpose of this work is the development of process for the valorization of these by-products, converting them in non-dangerous and profitable substances. For this process, most of the glycol can be recovered by means of vacuum distillation in order to reuse it in the glycolysis. On the other hand, the vacuum residue, containing the isocyanate part of the glycolysis by-products, was assayed as initiator in the synthesis of new polyols. Propoxylation of the initiator was carried out in different experimental conditions to obtain several polyether-polyols. Rigid polyurethane foams with suitable technical properties were synthesized with those polyols synthesized with the dangerous glycolysis by-products.     

废旧硬质聚氨酯泡沫塑料的木质素改性及再生

采用含有二乙二醇(DEG)和乙醇胺(ETA)的双组分解交联剂降解废旧硬质聚氨酯泡沫塑料(PU硬泡),并利用降解得到的低聚物多元醇与木质素复合制备出性能增强的再生PU硬泡。通过对制备的再生PU硬泡的红外光谱、密度、吸水率、抗压强度、热稳定性、导热系数、热重曲线等进行分析测试,考察m(DEG)∶m(ETA)对再生PU硬泡性能的影响。实验结果表明:m(DEG)∶m(ETA)=1∶3时废旧PU硬泡的降解效果最好;木质素加入量为2.0%(w)时再生PU硬泡的密度低、抗压强度高、保温性能良好,达到国家标准《建筑绝热用硬质聚氨酯泡沫塑料》(GB/T 21558—2008)的品质要求。     

Valorization of leather industry waste in polyurethane composites for reduced flammability

Journal of Material Cycles and Waste Management - Industrial wastes are considered a major cause of environmental pollution, and studies on valorizing these wastes and converting them into...     

Glycolysis of flexible polyurethane wastes using stannous octoate as the catalyst

Flexible polyurethane foam wastes can be advantageously treated by two-phase glycolysis to recover the polyols with an improved quality compared to single-phase processes. This reaction has been traditionally catalyzed by alkanolamines, titanium compounds, or acetates. Recently, the employment of new catalysts based on potassium and calcium octoates has opened up a new way to catalyze the glycolysis of polyurethanes. In this work, the use of stannous octoate, which has never before been applied in the glycolysis reactions of polyurethanes, is proposed. The catalytic activity of stannous octoate in such a process was studied. The decomposition rate and the purity of polyol obtained were greater than those obtained using other catalysts previously employed for this application.     

Reclaimed rockwool fibers for thermally stable palm oil-based polyurethane foam

Journal of Material Cycles and Waste Management - Due to its non-existent recyclability, industrial rockwool fiber wastes have caused environmental and waste management issues, which, therefore,...     

Revalorization of Macadamia nutshell residue as a filler in eco-friendly castor polyol-based polyurethane foam

Journal of Material Cycles and Waste Management - The use of lignocellulosic fibers as fillers in polymer matrices has aroused the interest of the scientific community and industrial sectors. In...     

Impact of the Jatoba shell residue amount on polyurethane foams based on castor polyol

Journal of Material Cycles and Waste Management - This study proposes an alternative for Jatoba shell residues as reinforcement in castor oil-based polyurethane (PU), obtaining an eco-friendly...     

Scaled-up and economic assessment approach of the split-phase glycolysis process for the recycling of flexible polyurethane foam wastes

The economic viability of the split-phase glycolysis process for the recycling of any kind of flexible polyurethane foam waste employing crude glycerol as cleavage agent has been demonstrated. First, experiments at pilot plant scale were carried out to check that the process can be extrapolated to larger scales. With the goal of scaling-up the process from laboratory scale to pilot plant, geometric similarity criteria were applied together with dynamic similarity for laminar flow in agitated tank reactors. Hence, a pilot plant installation was designed with geometrically similar equipment to those used for lab scale, obtaining analogous results in terms of recovered polyol properties. Then, the basic design of a split-phase glycolysis industrial plant with a capacity for treating 270 Tm per year of flexible PU foams scraps was proposed. Finally, the economic feasibility of such recycling process was confirmed because of the obtention of a Net Present Value (NPV) of 1,464,555€, with an Internal Rate of Return (IRR) of 27.99%, and a payback time between 4 and 5 years.

     

Gasification applicability study of polyurethane solid refuse fuel fabricated from electric waste by measuring syngas and nitrogenous pollutant gases

To recycle polyurethane foam waste generated from electric appliance recycling centers for use as fuel in a gasification process, polyurethane solid refuse fuel fabricated as pellets was analyzed for the characteristics of elemental composition, proximate analysis, heating value, and thermo-gravimetric testing. It has a high heating value of 29.06 MJ/kg with a high content of combustibles, which could be feasibly used in any thermal process. However, the nitrogen content, of up to 7 %, was comparably higher than for other fuels such as coal, biomass, and refuse-derived fuel, and may result in the emission of nitrogenous pollutant gases of HCN and NH₃. By conducting gasification experiments on polyurethane solid refuse fuel in a fixed-bed reactor, a syngas with a heating value of 9.76 kJ/m³ and high content of both H₂ and CO were produced with good gasification efficiency; carbon conversion 54 %, and cold gas efficiency 60 %. The nitrogenous pollutant gases in syngas were measured at the concentrations of 160 ppm hydrogen cyanide and 40 ppm ammonia, which may have to be reduced using proper cleaning technologies prior to the commercialization of gasification technology for polyurethane waste.