The influence of volume fraction of amorphous phase on corrosion resistance of Mg67Zn 29Ca 4 alloy

The aim of this study was to investigate the structure and corrosion resistance of amorphous, amorphous‐crystalline, and crystalline Mg₆₇Zn₂₉Ca₄ alloy for biodegradable applications. This paper presents a preparation method and results of the structural characterization and corrosion resistance analysis of the material. Samples were prepared in the form of 3 mm diameter rods. The structure of the alloy was examined with the use of X‐ray diffractometry and scanning electron microscopy. The thermal properties of the samples were examined with differential scanning calorimetry (DSC). Results of DSC analysis were used to determine heat treatment temperatures, allowing to obtain different fractures of crystalline phase in the material. Corrosion resistance of heat‐treated samples was investigated by immersion tests and electrochemical measurements performed in the simulated body fluid. The X‐ray diffraction results confirmed that the prepared Mg₆₇Zn₂₉Ca₄ alloy's structure is fully amorphous. After heat treatment, samples with different fractions of amorphous phase in the structure were obtained. Immersion tests of the samples showed that the structure significantly influenced corrosion resistance in examined materials. It should be pointed out, that certain amounts of crystalline phase in amorphous matrix can greatly improve the corrosion resistance of Mg₆₇Zn₂₉Ca₄ alloy.     

Anaerobic co-digestion of food waste and FOG with sewage sludge – realising its potential in Ireland

The severe environmental pollution in many countries is caused by indiscriminate discharge of large quantities of food waste (FW), fat oil and grease (FOG) and sewage sludge (SS) to the environment. There are many possible treatment routes, but anaerobic digestion (AD) is now well accepted for treating several kinds of organic wastes. But AD of FW alone presents some operational challenges because of substrates and variability. Anaerobic co-digestion of two or more substrates is better than single substrate digestion. This can use a plant’s unused capacity, in line with the trend to renewable energy. Co-digestion technology, although well established in many European countries, is still in its infancy in Ireland. There are problems with different regulatory arrangements. They should be resolved. The paper reviews anaerobic co-digestion technology is reviewed, with special focus on possible application in Ireland.     

Effect of different CaSO4 contents on CaSiO3-CaSO4 porous composite bone scaffolds by 3D gel-printing

Porous CaSiO₃-CaSO₄ composite scaffolds were successfully prepared by 3D gel-printing (3DGP) technology in this study. In order to further improve the degradation performance of pure CaSiO₃ scaffolds, the effect of different CaSO₄ doping contents on CaSiO₃-CaSO₄ composite scaffolds was studied. The results show that when the porous composite scaffolds were placed in simulated body fluid (SBF) for 5 weeks, the weight loss rate was 2.41% (CaSiO₃-1%CaSO₄), 3.97% (CaSiO₃-3%CaSO₄), 4.18% (CaSiO₃-5%CaSO₄), 6.87% (CaSiO₃-7%CaSO₄), and 12.93% (CaSiO₃-9%CaSO₄), respectively, which could be concluded that CaSO₄ doping has a significant effect on improving the biodegradability of CaSiO₃ scaffolds. And CaSO₄ doping can also effectively improve the compressive strength of composite scaffolds and that of CaSiO₃-3%CaSO₄ composite scaffolds was tested as 54.67 MPa, and the shrinkage rate of porous composite scaffolds was nearly 11.4%, which meets the application requirements of bone repairing engineering.     

Modifications to electrolytic respirometer systems for precise determination of BOD exertion kinetics in receiving waters

Modifications to an electrolytic respirometric system are described which facilitate precise measurements of BOD progressions for low substrate concentration (BOD₅ < 20 g m^?3) as found in natural waters receiving organic enrichment. Samples may be incubated at any desired temperature or dissolved oxygen concentration with automatic hourly monitoring of the BOD progression. Subsamples may be withdrawn at any time without interference to the measurement. The system is independent of atmospheric temperature and pressure fluctuations and has a detection sensitivity of 0.05 mg of oxygen. Nomographs are presented to enable the maximum dissolved oxygen deficit, and the “apparent lag” time to be estimated. CO₂ removal, which may result in an extended lag phase, need not be used for BOD values below 50 g m^?3 provided adequate buffering is supplied.     

Combined γ-ray irradiation-activated sludge treatment of humic acid solution from landfill leachate

Humic acid, which is a typical microbially refractory organic substance, was extracted from a landfill leachate. The humic acid solution (COD = 367 mg 1⁻¹; TOC = 293 mg 1⁻¹; BOD = 27 mg 1⁻¹) was applied to a batch scale activated sludge treatment after the modification of its biodegradability by γ-ray irradiation. The BOD increased to 64 mg 1⁻¹ by irradiation of 15 kGy (1.5 Mrad), while the COD and TOC decreased to 231 and 230 mg 1⁻¹, respectively. When the irradiated sample was treated with an activated sludge, the BOD decreased rapidly in 2–3 h to about 15 mg 1⁻¹ which was a similar value as the unirradiated sample was treated. The elimination efficiency of TOC by the sludge treatment was approximately equal to that obtained by irradiation of 15 kGy. These facts suggest a utility of applying microbial processes after radiation treatment of microbially refractory wastewaters.     

可生物降解PBAT/PLA/生物质垃圾袋的制备和表征

将聚己二酸/对苯二甲酸丁二酯（PBAT）和聚乳酸（PLA）进行共混,然后添加竹粉、木质素和秸秆粉,利用混合熔融造粒、挤出吹膜工艺制备了PBAT/PLA/生物质粉（BP）（质量比74.26/4.95/19.80）复合垃圾袋,并采用扫描电子显微（SEM）、红外光谱仪（FTIR）、X射线衍射测试（XRD）、热重分析仪（TG）及差示扫描量热仪（DSC）等对垃圾袋的微观形貌、组成、耐热性能、拉伸性能及抗漏性能进行了测试和表征,对其实用性进行了评估。结果表明,3种BP在PBAT/PLA基体中分散性较好,对薄膜结构和热性能几乎没有影响;添加竹粉和木质素材料的垃圾袋相比于添加秸秆粉的垃圾袋有明显的强度优势,强度提高了40 %以上。本研究对于降低PBAT/PLA垃圾袋的生产成本、促进生物降解材料的产业化应用具有重要借鉴意义。     

聚乳酸基油水分离材料研究进展

介绍了具有超疏水⁃超亲油和可生物降解特性的新型聚乳酸（PLA）油水分离材料,并对比分析了纯PLA和PLA基油水分离材料材料的研究和应用现状,得出利用PLA作为主原料或基体材料制备油水分离薄膜,不仅可以达到理想的油水分离效果,并且经过后处理后还可以多次循环使用,是目前理想的油水分离材料之一。最后,对PLA在油水分离应用领域的发展方向提出了建议。     

活性炭催化臭氧氧化工艺对焦化废水可生化性的改善

预氧化工艺常用来提高难降解工业废水的可生化性,其中以芬顿、臭氧应用最多。该文对这两种工艺提高煤化工行业焦化废水可生化性的性能做了对比,并提出了活性炭臭氧催化预氧化的改进工艺。试验表明单纯芬顿和臭氧预氧化并不能改善焦化废水的可生化性,而活性炭臭氧催化预氧化可以改善焦化废水的可生化性。经活性炭臭氧催化预氧化的焦化废水,BOD5/COD从0.16增加到0.24,COD去除率从72.5%提高到83.0%。     

Biodegradable organic acid-crosslinked alkali-treated gelatins with anti-thrombogenic and endothelialization properties

Abstract

Gelatins were crosslinked with organic acids and treated with alkali to impart to them endothelialization and anti-thrombogenic properties. These matrices were characterized by biochemical and physicochemical techniques. The amounts of residual amino groups in the matrices decreased with increasing crosslinker concentration. The matrices with the highest crosslinking densities showed excellent endothelial cell adhesion and proliferation. In addition, the adhesion of platelets and formation of fibrin networks on the matrices were suppressed with increasing crosslinker concentration. The matrices also exhibited excellent biodegradability, and the degradation rate decreased with increasing crosslinking density. All the organic acid-crosslinked alkali-treated gelatins showed excellent anti-thrombogenic and endothelialization properties, superior to those of glutaraldehyde-crosslinked alkali-treated gelatins.     

污水厌氧处理系统中溶解性微生物产物的研究进展

污水厌氧处理系统中产生的溶解性微生物产物(SMP)因其自身的性质、潜在危害性等逐渐引起国内外学者的重视。综述了国内外对厌氧SMP的研究成果,系统阐述了厌氧SMP的性质及影响其产生的运行参数。对其生成与降解数学模型的发展进行了综述。最后对今后厌氧SMP的研究方向作出了展望。