Extraction and characterization of hydroxyapatite-based materials from grey triggerfish skin and black scabbardfish bones

The conversion of food industry by-products to compounds with high added value is nowadays a significant topic, for social, environmental, and economic reasons. In this paper, calcium phosphate-based materials were obtained from black scabbardfish (Aphanopus carbo) bones and grey triggerfish (Balistes capriscus) skin, which are two of the most abundant fish by-products of Madeira Island. Different calcination temperatures between 400 and 1000°C were employed. Materials obtained from calcination of bones of black scabbard fish were composed by homogeneous mixtures of hydroxyapatite (Ca₁₀(PO4)₆(OH)₂, HAp) and β-tricalcium phosphate (β-Ca₃(PO₄)₂, β-TCP). Because of the high biocompatibility of HAp and the good resorbability of β-TCP, these natural biphasic materials could be very relevant in the field of biomaterials, as bone grafts. The ratio between HAp and β-TCP in the biphasic compound was dependent on the calcination temperature. Differently, the material obtained from skin of grey triggerfish contained HAp as the main phase, together with small amounts of other mineral phases, such as halite and rhenanite, which are known to enhance osteogenesis when used as bone substitutes. In both cases, the increase of calcination temperature led to an increase in the particles size with a consequent decrease in their specific surface area. These results demonstrate that from the fish by-products of the most consumed fishes in Madeira Island it is possible to obtain bioceramic materials with tunable composition and particle morphology, which could be promising materials for the biomedical field.     

Marine Phospholipids from Fishery By-Products Attenuate Atherosclerosis

In this study, the anti-atherosclerotic properties of three marine phospholipids (MPLs) extracts from fishery by-products including codfish roe, squid gonad, and shrimp head are verified. Their effects on key factors involved in atherosclerosis are examined and compared to explore whether the differences in their constitutions lead to the differences in the function. All three MPLs dampen oxidation of low- density lipoproteins (LDL) in vitro. Treating RAW264.7 macrophages and HUVECs endothelial cells with each MPLs ranging 10–100 µg mL⁻¹ does not decrease cell viability, yet ox-LDL caused cytotoxicity of both cells are alleviated by 50 or 100 µg mL⁻¹ MPLs treatment. In addition, the three MPLs reduce ox-LDL induced macrophage foam-like transition, mainly through inhibition of lipid uptake. Of the three MPLs, the one from squid gonad exhibits the best effect. On the other hand, all three MPLs modulate inflammatory responses, equally, by inhibiting the adhesion of monocytes to endothelial cells, and decreasing secretion of pro-inflammatory cytokines IL-6 and MCP-1. Using a high-cholesterol diet induced zebrafish model, it is found that all three MPLs, especially the one from squid gonad, alleviates cholesterol accumulation in early plaques, and decreases total cholesterol as well as lipid peroxide in vivo. Practical Applications: As a way of making the best of the increasingly scarce marine resources, valuable lipid components can be recovered from by-products and wastes from the fishery industry. Here, we tested the anti-atherosclerotic effects and the mechanisms of three MPLs extracted from codfish roe, squid gonad, and shrimp head. Our study provides further evidence that marine phospholipids extracted from fishery by-products could protect against atherosclerosis, and helps to elucidate the structure-function relationship of MPLs.     

Valorisation of potato wastes

Potato processing industry has a high degree of discarding, which currently has low added value being used primarily for animal feed. However, potato wastes offer a broad range of interesting components such as antioxidants, starch, protein or fibre with potential applications in the food and non-food industries. The recovery of these high valuable fractions using efficient multistage and multiproduct processes could be of great interest. This short review provides a general overview on the integral valorisation of potato wastes, offering an updated vision of the main residual parts generated during potato harvesting and processing, the high valuable obtained components focusing on the bioactive ones and the potential of the emerging extraction techniques over conventional ones. In addition, innovative applications are discussed to highlight the scientific and applied interest of these underutilised and undervalued fractions and to emphasise the integral valorisation of raw materials.     

Ozonation of CI Reactive Black 5 using rotating packed bed and stirred tank reactor

This study investigates the ozonation of CI Reactive Black 5 (RB5) by using the rotating packed bed (RPB) and completely stirred tank reactor (CSTR) as ozone contactors. The RPB, which provides high gravitational force by adjusting the rotational speed, was employed as a novel ozone contactor. The same ozone dosage was separately introduced into either the RPB or the CSTR for the investigation, while the experimental solution was continuously circulated within the apparatus consisting of the RPB and CSTR. The decolorization and mineralization efficiencies of RB5 in the course of ozonation are compared for these two methods. Moreover, the dissolved and off‐gas ozone concentrations were simultaneously monitored for the further analysis. As a result, the ozone mass transfer rate per unit volume of the RPB was significantly higher because of its higher mass transfer coefficient and gas–liquid concentration driving force. Furthermore, ozonation kinetics was found to be independent of the gravitational magnitude of an ozone gas–liquid contactor. Therefore, the results suggest employing RPBs as ozone‐contacting devices with the advantage of volume reduction. The experimental results, which can be used for further modeling of the ozonation process in the RPB, also show the requirement of correct design for the RPB. Consequently, the present study is useful for the understanding of practical application of RPBs. Copyright © 2004 Society of Chemical Industry     

On the suitability of agricultural by-products for the manufacture of granular activated carbon

An investigation of several agricultural by-products revealed that their suitability for activated carbon production is not determined by general material-specific features (elemental composition) but by type-specific features. A coarse-cellular structure (as in wood), which is indicated by porosities of the raw materials higher than 35% is disadvantageous. A specific change in the properties of cokes (porosity, density, hardness) is possible by varying the conditions of pyrolysis. By rapid heating in the pyrolysis step, for instance, macroporous residues are produced. Temperature and burnoff have the greatest influence on the quality of the activated carbon during the activation step. Of the investigated materials, coconut shells yield granular activated carbon of the highest quality. The following order of suitability of raw materials for activated carbon production was established: coconut shells> peach stones> plum stones> hazelnut shells> walnut shells> cherry stones.     

臭氧氧化-光催化降解水中的五氯酚

利用臭氧氧化-光催化技术降解水中的有机污染物五氯酚(PCP)。对比了紫外光照射、臭氧氧化、光催化、臭氧氧化-光催化4种方法降解PCP的情况。考察了臭氧氧化-光催化体系中臭氧流量、臭氧产量、PCP初始质量浓度、pH和CO23-等因素对PCP降解率的影响。实验结果表明,臭氧氧化-光催化法比单独使用紫外光照射、臭氧氧化、光催化法更能有效的去除PCP;增加臭氧流量和臭氧产量有利于提高PCP的降解率;降低PCP的初始浓度,PCP的降解率显著提高;pH对PCP的降解效果影响不明显;CO23-的存在显著降低了PCP的降解率。在臭氧氧化-光催化体系中,除臭氧直接氧化降解PCP外,臭氧与TiO2协同作用产生的.OH对PCP的降解也起到了重要作用。     

Efficacy and Safety Evaluation of Ozonation to Degrade Aflatoxin in Corn

ABSTRACT: This study determined the efficacy and safety of ozonation in degrading aflatoxin in corn. Ozonation (10 to 12 wt%) reduced aflatoxin levels by 92% and no reversion to the parent compound was observed. Ozonation had minimal effect on fatty acids of uncontaminated corn, but had significant effect on fatty acids of contaminated corn. Crude extracts showed no mutagenic potential in the Ames assay using TA98 and TA100. Clean-up using hexane increased their mutagenic potentials. Clean-up using Mycosep columns increased the mutagenic potentials 18 to 617%. Hexane extracts from ozone-treated contaminated corn had lower inhibitory effect. This suggested that a fat-soluble mutagen is being formed or natural inhibitors of mutagenicity are being destroyed.     

Product and by-product formation in laboratory studies on disinfection electrolysis of water using boron-doped diamond anodes

Boron-doped diamond (BDD) electrodes were studied with respect to the formation of inorganic by-products in water electrolysis. Experiments in non-divided cells were performed with systems containing sulphate, chloride, chlorite, chlorate and nitrate ions. Discontinuous experiments in thermostated cells with rotating disk diamond anodes and expanded mesh IrO₂ cathodes were carried out at 20 °C. Current density was varied between 50 and 300 A m⁻². Ion chromatography was mainly used for species detection.

It was not possible to demonstrate the decomposition of sulphate although a slight tendency seems to exist in some experiments. Hydrogen peroxide is one of the anodic and cathodic by-products. Active chlorine is detectable at higher chloride concentrations compared with the use of mixed oxide anodes (MIO). One reason for this is the reaction of formed chlorine with ozone or hydrogen peroxide. Chlorate can be formed electrolysing chloride, hypochlorite and chlorite solutions. Perchlorate formation was detected. Cathodic processes are responsible for the formation of nitrite ions and ammonia. If chlorine is present, the formation of monochloramine is one possible side reaction. Results show that the processes are very complex. Reaction spectra may vary from case to case. Perchlorate formation is a high risk in drinking water treatment.     

Catalytic ozonation of NH4+-N in wastewater over composite metal oxide catalyst

Large amounts of water containing-ammonium nitrogen(NH₄⁺-N)have attracted increasing attention.Catalytic ozonation technology,involving the generation of hydroxyl radical(OH)with strong oxidation ability,was originally utilized to degrade organic-containing wastewater.In this paper,Ce/MnOx composite metal oxide catalysts prepared with different preparation conditions were used to degrade wastewater containing inorganic pollutant(NH₄⁺-N).The as-prepared catalyst features were characterized using X-ray diffraction(XRD),Brunauer-Emmett-Teller method(BET),scanning electron microscopy(SEM),energy dispersive X-ray spectroscopy(EDS),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and H₂-temperature programmed reduction(H₂-TPR)techniques.The results show that the catalyst,prepared by conditions with precipitant Na₂CO₃ and Ce/Mn molar ratio 1:2 calcined at 400℃for 3 h in pH 11.0,displays the optimal performance,with the removal rate of NH₄⁺-N and selectivity to gaseous nitrogen,88.14 wt%and 53.67 wt%,respectively.The effects of several operating factors including solution pH,initial NH₄⁺-N concentrations and scavengers were evaluated.In addition,XRD patterns of catalyst with the best performance and the comparative study on decontamination of NH₄⁺-N by various processes(O₃,catalyst and catalyst/O₃)show that the primary metal oxides are CeO₂ and MnO₂ in Ce/MnOx composite metal oxide catalysts,which have a synergistic effect on the catalytic ozonation of NH₄⁺-N,and the new phase MnO₂ plays a great role.After 5 consecutive use cycles,the degradation efficiency is declined slightly,and can still achieve better than 70 wt%over 1 h reaction.Additionally,the application of catalytic ozonation for actual wastewater on the removal rate of NH₄⁺-N was investigated.Possible mechanism and degradation pathway of NH₄⁺-N were also proposed.In a word,the application of CeO₂-MnO₂ composite metal oxide catalysts in catalytic ozonation can be regarded as an effective,feasible and promising method for the treatment of NH₄⁺-N.     

新型组合工艺对微污染原水中有机污染物和消毒副产物前体物的去除

本采用中试试验装置研究了生物陶粒过滤一微絮凝砂滤一活性炭吸附组合工艺，对微污染原水中有机污染物和消毒副产物前体物的去除效果。在原水UV254为0．047～0．065cm^-1，DOC为2．70～4．10mg／L，TOC为3．50～5．00mg／L的条件下，组合工艺对UV254，DOC、TOC平均去除率分别为98．4％、74．1％、69．2％。色-质联机分析结果表明，经组合工艺处理水中有机物由54种降至25种。组合工艺出水中三卤甲烷总含量不及常规工艺出水中该物质含量的五分之一。组合工艺能有效控制和消除水中有机物的污染，提供安全的优质饮用水。