武荣兰
One-step preparation of robust elastic plastic polyvinyl chloride sponges with a layered structure for highly efficient separation of water-in-oil emulsions
To address the environmental pollution and human health issues caused by oily wastewater and PVC plastic waste, a practical zero-waste solution has been developed. In this study, PVC sponges with superlipophilic and superhydrophobic properties were prepared using vapor induced phase inversion and recycling PVC food wrap, without the use of any additives. This sponge effectively separates oil and water. The pore size of PVC sponges could be adjusted by varying the PVC concentration and solvent ratio, which led to improvements in pore density, specific surface area, porosity, oil sorption capacity, and emulsion separation performance. The emulsion separation experiment demonstrated that the 7 wt% PVC sponge (7-0-1) can efficiently separate oil from water-in-oil emulsion, with excellent separation efficiency and a flux of 161.5 L m-2⋅h-1⋅bar-1. Moreover, the sponge exhibits impressive properties such as elastic recovery, flexibility, self-cleaning, and mechanical strength. Remarkably, even after recycling, the sponge maintains its hydrophobicity and emulsion separation performance. This hydrophobic sponge has great potential for mass production and oil–water separation such as in oil spill accidents.
针对含油废水和聚氯乙烯塑料废弃物造成的环境污染和人类健康问题，开发了一种实用的零废物解决方案。本研究在不使用任何添加剂的情况下，采用气相转化和回收PVC食品包装制备了具有超亲脂和超疏水性能的PVC海绵。这种海绵能有效地分离油和水。通过改变PVC浓度和溶剂配比，可以调节PVC海绵的孔径，从而提高PVC海绵的密度、比表面积、孔隙率、吸油能力和乳液分离性能。乳液分离实验表明，7 wt% PVC海绵（7-0-1）可有效分离油包水乳液，分离效率高，分离通量为161.5 L⋅m-2⋅h-1⋅bar-1。此外，这种海绵表现出令人印象深刻的性能，如弹性恢复、柔韧性、自清洁和机械强度。值得注意的是，即使在回收后，海绵仍保持其疏水性和乳液分离性能。这种疏水海绵在大规模生产和石油泄漏事故等油水分离方面具有很大的潜力。
全文链接：https://doi.org/10.1016/j.cej.2023.144752
Oil absorption stability of modified cellulose porous materials with super compressive strength in the complex environment
The occurrence of oil spills has severe damage upon both the environment and human health. Hence, the development of a green, recyclable, complex environment resistant, and efficient oil–water separation aerogel is required in order to effectively absorb marine or industrial oil. In this study, modified cellulose/N,N’-methylenebisacrylamide/tannin (PCMT) composite porous materials were prepared utilizing the sol–gel method and were modified with tertbutyl acrylate. PCMT possesses a three-dimensional interpenetratingporous structure, exhibiting remarkable oil–water separation performance and excellent compressive strength (PCMT can capable of bearing 7000 times its own weight; PCMT can endure 290.3 kPa pressure at 80% strain when the amount of tannin is 0.2 g). The unique pore structure of PCMT engenders differential oil adsorption capacities (PCMT0, PCMT0.05, PCMT0.1, and PCMT0.2 evince higher adsorption capacities for petroleum ether and dichloromethane, n-hexane and dichloromethane, toluene, and toluene and dichloromethane, respectively). Of critical import, PCMT demonstrates exceptional adaptability to complex environments, wherein the porous materials maintain good hydrophobicity and oil absorption capacity under conditions of vigorous stirring, a wide pH range (1–14), a wide temperature range (4–160°C), ultraviolet irradiation (8 h), and tape peeling (10 times). Moreover, the porous materials may be employed for the recovery of oil through simple mechanical extrusion, thus demonstrating certain economic significance and the application potential in the treatment of oil spills.
石油泄漏的发生对环境和人类健康都造成了严重的危害。因此，开发一种绿色、可回收、耐复杂环境、高效的油水分离气凝胶是有效吸收海洋或工业用油的必要条件。本研究采用溶胶-凝胶法制备了改性纤维素/N,N’-亚甲基双丙烯酰胺/单宁(PCMT)复合多孔材料，并用丙烯酸叔丁酯对其进行改性。PCMT具有三维互穿的多孔结构，优异的油水分离性能和抗压性能(PCMT可承受自身重量的7000倍；当单宁用量为0.2 g时，PCMT在80%应变下可承受290.3 kPa的压力)。PCMT独特的孔隙结构导致其不同的油吸附能力(PCMT0、PCMT0.05、PCMT0.1和PCMT0.2分别对石油醚和二氯甲烷、正己烷和二氯甲烷、甲苯、甲苯和二氯甲烷具有较高的吸附能力)。重要的是，PCMT表现出卓越的复杂环境适应性，其多孔材料在剧烈搅拌、宽pH范围(1-14)、宽温度范围(4-160oC)、紫外线照射(8小时)和胶带剥离(10次)的条件下仍保持良好的疏水性和吸油能力。此外，多孔材料可以通过简单的机械挤压来回收石油，从而显示出一定的经济意义。
全文链接：https://doi.org/10.1007/s10570-023-05322-5
DMAEMA-grafted cellulose as an imprinted adsorbent for the selective adsorption of 4-nitrophenol
4-Nitrophenol is a highly toxic environmental pollutant. It is a challenge to selectively remove it from a mixture of various pollutants. Herein, we report a study on the selective adsorption of 4-nitrophenol by using molecularly imprinted polymers (MIPs). The imprinted polymer was synthesized using cellulose as a framework, onto which, the complex of the imprinting molecule (i.e., 4-nitrophenol) and a candidate material [namely, 2-(dimethylamino) ethyl methacrylate. DMAEMA] was grafted. The obtained MIP showed an excellent adsorption capacity with good selectivity. Also, the adsorption of 4-nitrophenol by the obtained MIP was fast and the adsorbent exhibited good recyclability. The thermodynamics and kinetics of the adsorption process of 4-nitrophenol by MIP was thoroughly studied, where an otherwise-equivalent non-imprinted polymer was used as a control in the experiments. The selectivity of the MIP adsorbent for 4-niteophenol was evaluated by two types of experiments: (1) adsorption experiments in single-component adsorbate systems (containing 4-nitrophenol, 3-nitrophenol, catechol, or hydroquinone), and (2) competitive adsorption experiments in binary adsorbate systems (containing 4-nitrophenol plus either 3-nitrophenol, catechol or hydroquinone). The selectivity coefficient for 4-nitrophenols was twice of those of other phenols (that were all around 2), indicative of the extent of the affinity of MIPs to these phenolic compounds. The recyclability of the adsorbent was evaluated for 5 adsorption–desorption cycles, where the adsorption capacity of the last cycle remained over 90.2% of that of the first cycle.
4-硝基苯酚是一种剧毒的环境污染物。从各种污染物的混合物中选择性地去除它是一个挑战。本文报道了分子印迹聚合物(MIPs)对4-硝基苯酚选择性吸附的研究。该印迹聚合物是以纤维素为骨架，通过接枝聚合印迹分子(即4-硝基苯酚)与候选材料[即甲基丙烯酸二甲氨基乙酯(DMAEMA)]的配合物制备而成。所制备的MIP具有优良的吸附性能和良好的选择性，其对4-硝基苯酚具有较快的吸附速度，且该吸附剂具有良好的可回收性。研究了MIP吸附4-硝基苯酚的热力学和动力学过程，并以非印迹聚合物作为对照。通过两类实验来评价MIP吸附剂对4-硝基苯酚的选择性:(1)在单组分吸附体系(含4-硝基酚、3-硝基苯酚、邻苯二酚或对苯二酚)中的吸附实验，以及(2)在二元吸附体系(含4-硝基酚加3-硝基苯酚、邻苯二酚或对苯二酚)中的竞争吸附实验。4-硝基苯酚的选择性系数是其他酚类化合物的两倍(都在2左右)，这表明MIPs对这些酚类化合物的亲和力程度。通过5次吸附-解吸循环对吸附剂的可回收性进行了评价，最后一次循环的吸附容量保持在第一次循环的90.2%以上。
全文链接：https://doi.org/10.1007/s10570-021-03920-9
UV and chemical aging alter the adsorption behavior of microplastics for tetracycline
This study evaluates the “vector” effects of different microplastics (MPs) on coexisting pollutants. The adsorption of tetracycline was studied on biodegradable plastics poly(butylene adipate-co-terephthalate) (PBAT) and nonbiodegradable plastics polystyrene (PS), polypropylene (PP), and polyethylene (PE) after UV aging and chemical aging. The physicochemical properties of PBAT changed more obviously after UV radiation and chemical aging comparing to PS, PP and PE. Pores and cracks appear on the surface of aged PBAT. The crystallinity increased from 29.2% to 52.62%. In adsorption experiments, pristine and aged PBAT had strong vector effects on the adsorption of tetracycline than PS, PP and PE. The adsorption capacity of tetracycline on PBAT was increased from 0.7980 mg g− 1 to 1.2669 mg g− 1 after chemical aging. The adsorption mechanism indicated that electrostatic interactions and hydrogen bonds contribute to the adsorption process. In addition, for the adsorption of tetracycline on PS, π-π interaction was the main cause, and the adsorption mechanism was not considerably changed by aging. In conclusion, this study demonstrates that biodegradable plastics have substantial vector effect on coexisting pollutants at the end of their life cycle, this contributes to assessment of the risk from microplastic pollution.
本研究评估了不同微塑料(MPs)对共存污染物的“载体”效应。研究了生物降解塑料聚己二酸丁二酯(PBAT)和非生物降解塑料聚苯乙烯(PS)、聚丙烯(PP)、聚乙烯(PE)在紫外线老化和化学老化后对四环素的吸附。与PS、PP和PE相比，PBAT经紫外线照射和化学老化后的理化性能变化更为明显。老化后的PBAT表面出现气孔和裂纹。结晶度由29.2%提高到52.62%。在吸附实验中，原始PBAT和老化PBAT对四环素的吸附载体效应强于PS、PP和PE。化学老化后，PBAT对四环素的吸附量由0.7980 mg g−1提高到1.2669 mg g−1。进一步研究表明静电相互作用和氢键参与了吸附过程。此外，对于四环素在PS上的吸附，π-π相互作用是主要原因，吸附机理不受老化的影响。论文研究结果表明，生物降解塑料在其生命周期结束时对共存污染物具有显著的媒介效应，这有助于评估微塑料污染的风险。
全文链接：https://doi.org/10.1016/j.envpol.2022.120859
Adsorption behavior of UV aged microplastics on the heavy metals Pb(II) and Cu(II) in aqueous solutions
As the “vector” of heavy metals in the aquatic environment, microplastics (MPs) have a great influence on the migration and transformation of heavy metals. In this study, the adsorption of polypropylene (PP), polyethylene (PE) and polystyrene (PS) on two models of heavy metals after UV aging and environmental variables (ionic coexistence, pH, salinity, and fulvic acid) were comprehensively explored on adsorption. The results show that new oxidation functional groups are formed and their hydrophilicity is enhanced after MPs aging. As a result, the adsorption experiments showed that the adsorption of contaminants by UV aged MPs exceeds that of pristine MPs. The adsorption amounts of Pb(II) and Cu(II) by PP, PE and PS increased by 1.45, 1.46, 1.25 and 1.63, 1.39, 1.22 times, respectively. Adsorption kinetic data were more consistent with the pseudo-second-order kinetic model, proving chemisorption to be the mechanism governing the interaction between metal ions and MPs. The Freundlich model could accurately predict the heavy metal adsorption isotherms on MPs, showing that nonhomogeneous multilayer adsorption dominates the process. In Pb(II)–Cu(II) binary composite system, metal ion adsorption capacity on MPs is less than that of the single system adsorption capacity, which proves that there is a specific inhibitory effect between coexisting ions. Additionally, external factors like pH, salinity, and fulvic acid content have a big impact on adsorption behavior. According to mechanism analysis, the adsorption process mainly relies on electrostatic interaction, surface complexation, and van der Waals force.
微塑料作为水生环境中重金属的“载体”，对重金属的迁移转化有很大的影响。本研究探讨了聚丙烯(PP)、聚乙烯(PE)和聚苯乙烯(PS)在UV老化后对两种模式重金属的吸附以及环境变量(离子共存、pH、盐度、黄腐酸)对吸附的影响。结果表明，MPs老化后形成了新的氧化官能团，亲水性增强。因此，吸附实验表明，UV老化MPs对污染物的吸附超过了原始MPs。PP、PE和PS对Pb(II)和Cu(II)的吸附量分别提高了1.45、1.46、1.25倍和1.63、1.39、1.22倍。吸附动力学数据更符合拟二级动力学模型，证明化学吸附是控制金属离子与MPs相互作用的机制。Freundlich模型能较准确地预测MPs对重金属的吸附等温线，表明非均质多层吸附占主导地位。在Pb(II) -Cu (II)二元复合体系中，金属离子对MPs的吸附容量小于单一体系的吸附容量，证明共存离子之间存在特异性抑制作用。此外，pH、盐度、黄腐酸含量等外部因素对吸附行为影响较大。机理分析表明，吸附过程主要依靠静电相互作用、表面络合作用和范德华力。
全文链接：https://doi.org/10.1016/j.chemosphere.2022.137439
Partially carbonized wastepaper with excellent mechanical strength for oil-water and emulsion separation
Background: Taking the treatment of oily sewage and the recycling of wastepaper as the starting point, the idea of using waste to treat waste was used to treat the swage with aerogels made of wastepaper. Methods: Porous ultralight Fe-functionalized cellulose carbon aerogels (CPFe) were synthesized using wastepaper as raw material through FeCl3 impregnation and low-temperature carbonization. Findings: CPFe aerogels exhibit excellent physicochemical properties, such as: low density (0.0284 g/cm3 ), high porosity (97.32%), and selective absorption capacity for various oil products. The absorption capacity of chloroform reached 62.8 g/g. In addition, it exhibits excellent capacity in emulsion separation for both o/w and w/o types. Droplet size of w/o emulsion reduced by two orders of magnitude. CPFe aerogel is a low-cost, renewable, environmentally friendly material and suitable for large-scale production. It is expected to have broad applications in pollution remediation.
本论文以含油污水处理和废纸回收为出发点，以废治废的思路，用废纸制成的气凝胶处理污水。以废纸为原料，经FeCl3浸渍和低温碳化制备多孔超轻铁功能化纤维素碳气凝胶(CPFe)。结果发现CPFe气凝胶具有低密度(0.0284 g/cm3)、高孔隙度(97.32%)和对多种油品选择性吸附能力等优异的理化性质。对氯仿的吸附量达到62.8 g/g。此外，它对o/w型和w/o型乳化液均表现出优异的分离能力。w/o乳液的液滴尺寸减小了两个数量级。CPFe气凝胶是一种低成本、可再生、环保的材料，适合大规模生产。在污染修复中具有广阔的应用前景。
全文链接：https://doi.org/10.1016/j.jtice.2023.104816
Ultra-fast degradation of phenolics and dyes by Cu2O/Cu catalysts: Synthesis and degradation kinetics
The complex and time-consuming character of the current methods to synthesize cuprous catalysts hampers use of such compounds as replacements for noble metal catalysts for the degradation of organic pollutants. Herein, we report on the development of a simple one-pot method for synthesis of Cu2O/Cu nanoparticles. The method was comprised of adding benzyl alcohol during the process of nanoparticle synthesis, where the amount of benzyl alcohol used determined the content of Cu in the obtained nanoparticles. A thorough physicochemical characterization was carried out for the synthesized nanoparticles, where it was found that they could act as catalysts for ultra-fast degradation of phenolics and dyes. Thus, their catalytic activity for the degradation of 4-nitrophenol, methyl orange, and Congo red were evaluated, where pseudo-first-order kinetics were observed. The percentage degradation and rate constant (kapp) values were, respectively, 98% (in 60 s) and kapp= 61.23 × 10− 3 s − 1 for 4-nitrophenol, 96% (in 100 s) and kapp = 31.5 × 10− 3 s − 1 for methyl orange, and 97% (in 100 s) and kapp= 35.5 × 10− 3 s − 1 for Congo red. Comparisons with previously reported cuprous catalysts for degradation of these compounds revealed that the Cu2O/Cu nanoparticles of the present paper exhibited the fastest degradation rates.
目前合成铜催化剂的方法复杂且耗时，阻碍了这些化合物作为贵金属催化剂的替代品用于降解有机污染物。本论文报告了一种简单的一锅法合成Cu2O/Cu纳米颗粒的发展。该方法是在纳米颗粒合成过程中加入苯甲醇，其中苯甲醇的用量决定了纳米颗粒中铜的含量。对合成的纳米颗粒进行了彻底的物理化学表征，发现它们可以作为苯酚和染料超快速降解的催化剂。因此，它们对4-硝基苯酚、甲基橙和刚果红降解的催化活性进行了评估，其中观察到伪一级动力学。4-硝基苯酚的降解率和速率常数(kapp)分别为98% (60 s)和kapp= 61.23 × 10−3 s−1，甲基橙为96% (100 s)和kapp= 31.5 × 10−3 s−1，刚果红为97% (100 s)和kapp= 35.5 × 10−3 s−1。与先前报道的铜催化剂降解这些化合物的比较表明，本文的Cu2O/Cu纳米颗粒表现出最快的降解速率。
全文链接：https://doi.org/10.1016/j.jece.2021.105505
Degradation of tetracycline by visible light over ZnO nanophotocatalyst
ZnO material can only absorb ultraviolet light. However, tetracycline (TC) can sensitize semiconductors to produce visible light activity. The application of intrinsic ZnO for visible light degradation of TC is a new discovery. The ZnO nanostructures were synthesized by the precipitation method with sodium dodecyl sulfate (SDS) as the structure guide. The catalytic activity of intrinsic ZnO to degrade high concentrations of TC under visible light irradiation was investigated. Significant findings: The addition of SDS changed the morphology of ZnO and reduced its average size to 55.5 nm. In the visible light photocatalytic degradation, SDS also enhanced the adsorption of TC on the surface of ZnO and promoted the formation of TC-SDS/ZnO surface complexes at the defects. The results showed that the degradation rate of TC by SDS/ZnO is 49.0%, which is 2.51 times that of commercial ZnO. UV-Vis DRS proves that TCSDS/ZnO has visible light response, TC as a photosensitizer absorbs visible light and excites ZnO with visible light response. Radical trapping experiments combined with ESR tests jointly proved that •O2 − and •OH play vital roles in the degradation of TC, finally the degradation mechanism was proposed.
氧化锌材料只能吸收紫外线。然而，四环素(TC)可以敏化半导体产生可见光活性。本征ZnO在TC可见光降解中的应用是一个新发现。本论文以十二烷基硫酸钠(SDS)为结构导向，采用沉淀法合成了氧化锌纳米结构。研究了本征氧化锌在可见光照射下降解高浓度TC的催化活性。重要发现:SDS的加入改变了ZnO的形貌，使其平均尺寸减小到55.5 nm。在可见光光催化降解中，SDS还增强了TC在ZnO表面的吸附，促进缺陷处TC-SDS/ZnO表面配合物的形成。结果表明，SDS/ZnO对TC的降解率为49.0%，是商用ZnO的2.51倍。UV-Vis DRS证明TCSDS/ZnO具有可见光响应，TC作为光敏剂吸收可见光，激发ZnO具有可见光响应。自由基捕获实验和ESR实验共同证明了•O2−和•OH在TC的降解中起着至关重要的作用并提出了降解机理。
全文链接：https://doi.org/10.1016/j.jtice.2022.104422
