The effect of growth rate and ageing on colour variation of European pond turtles

Many chelonians have colourful dots, patches and stripes throughout their body that are made up, at least in part, of carotenoids. Therefore, turtles are very suitable models to study the evolution and functionality of carotenoid-based colouration. Recent studies suggested a close link between colouration and immune system in these taxa. However, more research is needed to understand the role of these colourful stripes and patches in turtle visual signalling. The purpose of this study was to explore the relationship between growth rate and colouration in European pond turtles. In particular, we wanted to answer the question of whether there is a trade-off between growth and colour expression. We also aimed to explore the effect of body size and age on colour variation. Turtles from a reintroduction-breeding program were recaptured, weighed and measured over an 8-year period to estimate their growth rates and age. We also measured with a spectrometer the reflectance of colour patches in two different body parts: shell and forelimb. We found that turtles with a faster growth rate had brighter limb stripes independently of their age. On the other hand, shell colouration was related to body size with larger turtles having brighter shell stripes and higher values of carotenoid chroma. Our results suggest that fast-growers may afford to express intense colourful limb stripes likely due to their higher intake of carotenoids that would modulate both growth and colour expression. However, shell colouration was related to body size probably due to ontogenetic differences in the diet, as juveniles are strictly carnivorous while adults are omnivorous. Alternatively, shell colouration might be involved in crypsis as the shell is visually exposed to predators.     

Assessment and prediction of the effect of ageing on the adsorption of nonylphenol in black carbon-sediment systems

Black carbon (BC) is a promising sediment amendment, as proven by its considerable adsorption capacity for hydrophobic organic pollutants and accessibility, but its reliability when used for the removal of pollutants in natural sediments still needs to be evaluated. For example, the ageing process, resulting in changing of surface physicochemical properties of BC, will decrease the adsorption capacity and performance of BC when applied to sediment pollution control. In this study, how the ageing process and BC proportion affect the adsorption capacity of BC-sediment systems was modelled and quantitatively investigated to predict their adsorption capacity under different ageing times and BC additions. The results showed that the ageing process decreased the adsorption capacity of both BC-sediment systems, due to the blockage of the non-linear adsorption sites of BC. The adsorption capacity of rice straw black carbon (RC)-sediment systems was higher than that of fly ash black carbon (FC)-sediment systems, indicating that RC is more efficient than FC for nonylphenol (NP) pollution control in sediment. The newly established model for the prediction of adsorption capacity fits the experimental data appropriately and yields acceptable predictions, especially when based on parameters from the Freundlich model. However, to fully reflect the influence of the ageing process on BC-sediment systems and make more precise predictions, it is recommended that future work considering more factors and conditions, such as modelling of the correlation between the adsorption capacity and the pore volume or specific surface area of BC, be applied to build an accurate and sound model.     

碳酸锶生产中锶盐废渣的危险特性分析

采集西南某碳酸锶生产企业不同年份下碳酸锶生产过程中产生的锶盐废渣(下称“锶渣”),分析其重金属浓度、浸出浓度及遇酸反应生成的H₂S浓度,研究锶渣的危险特性。结果表明:锶渣中Sr浓度最高,最大值为175 000 mg/kg,均值为112 000 mg/kg;其次是Ba浓度,最大值和均值分别为6 020和3 420 mg/kg;其他重金属如As、Cr、Cu、Ni、Pb、Be和Cd浓度均低于100 mg/kg;锶渣中Sr的浸出浓度最高,其最大值和均值分别为360和180 mg/L,Ba、Pb和As的浸出浓度均较低;锶渣中的硫化物遇酸反应生成H₂S,其浓度均值为0.23 mg/kg,最大值为0.45 mg/kg;锶渣中重金属的浸出浓度和遇酸生成H₂S的浓度总体上随着堆存时间延长而降低。     

两种电解体系对苯酚降解效果的对比

使用 Ti/IrO₂RuO<₂阳极、电还原氧气产生 H₂O₂的碳/聚四氟乙烯(C/PTFE)气体扩散阴极,分别在无隔膜与隔膜(隔膜材料为涤纶)电解体系中,研究了电化学催化氧化降解苯酚的效果.在无隔膜与隔膜2种电解体系中,电解80min后,H₂O₂的稳定浓度分别是5.6mg/L和8.5mg/L.2 种电解体系中苯酚的去除率均可达到 100%,但隔膜电解体系中 COD 去除率为 81.2%,无隔膜电解体系 COD 去除率为 71.7%.在 2 种电解体系中通过 HPLC 分析检测到中间产物为苯醌和一些短链的脂肪酸.对于阴、阳极降解苯酚的机理推测,2 种体系是相似的,但对隔膜电解体系,阴极室的碱性条件有利于氧的阴极还原生成 HO₂ ,并进一步形成 HO·和 O₂·自由基,从而对苯酚有较好的去除效果.     

蒙脱土-腐殖酸复合体制备及其对锶的吸附性能研究

为探究土壤胶体对放射性核素锶的吸附机制,选取典型无机矿物蒙脱土和腐殖酸制备有机-无机复合胶体,并研究了其对锶的吸附性能.实验结果表明,人工复合体的腐殖酸负载量可达到2.97%,并且添加腐殖酸会改变蒙脱土的形貌.复合体对锶的吸附量达到6.86mg/g,通过对复合体吸附锶的动力学拟合发现,吸附过程更符合二级动力学模型.吸附过程在10min后到达平衡,低温时去除率更高,15℃时为72.29%.当pH值由5增加到9时,去除率的变化范围在1%~2%之间.而离子强度对吸附有明显的影响,0.1mol/L时去除率较0.001mol/L时的去除率同比下降20%~60%.同时去除率随有机物浓度的增大而提高,从0到60mg/L时去除率快速增长,60mg/L时去除率为75.36%,随后去除率增长进入平缓期.     

颗粒粒径对玉米秸秆生物碳吸附锶的影响

以玉米秸秆为原材料,采用限氧裂解法于350℃下制备了不同粒径的生物碳(BC-9.31、BC-20.26、BC-60.77、BC-71.07、BC-101.9,数字代表样品的中值径μm),研究颗粒粒径对生物碳吸附锶的影响.结果表明:生物碳的颗粒粒径对核素锶的吸附速率和吸附容量均有显著影响.生物碳对锶的吸附动力学符合准二级动力学模型(R2,0.99),颗粒最细的BC-9.31吸附速率最大(4.48 mg·g~(-1)·h~(-1)).随着颗粒粒径的增加,锶的吸附速率呈指数降低,其吸附速率差异高达20倍.生物碳对锶的吸附等温曲线符合准Langmuir模型(R2,0.94~0.99),饱和吸附容量为9.09~23.81 mg·g~(-1).随着粒径的增大,锶的吸附容量先降低后增高又降低,粒径最小的BC-9.31(23.81 mg·g~(-1))吸附容量最大,吸附容量最小的则是BC-60.77(9.09 mg·g~(-1)),两者相差2.6倍.pH对生物碳吸附锶具有重要影响.在溶液pH值较低时(1.93~4.74),对锶的吸附去除率急剧增加(3.94~9.17倍);而pH值较高时(4.74~11.85),吸附去除率缓慢提高(1.11~1.68倍).pH值也是颗粒粒径影响的重要参数,随pH值增加颗粒粒径对生物碳吸附锶的影响程度显著减小.生物碳极性指数与锶饱和吸附量和吸附速率均呈正相关关系,表明极性官能团是锶的重要吸附位点.     

微波预处理面包酵母对锶的吸附研究

采用微波预处理的面包酵母作为生物吸附剂吸附处理Sr2＋,研究了其吸附特性、生物吸附动力学、吸附平衡过程和吸附机理.实验结果表明,微波预处理能有效提高酵母的吸附效能.酵母对Sr2＋吸附10min即可达到平衡,吸附过程可以很好地用准二级动力学方程来描述（R2=0.9999）,平衡吸附量qe为4.69mg·g^-1,二级吸附...     

重庆地区锶盐产业可持续发展对策研究

描述了锶的特性;介绍了锶盐在现代工业、化工及军事工程中不可替代的作用;分析了重庆地区锶矿开采、锶盐加工中存在的问题;提出了解决制约锶盐产业可持续发展瓶颈问题的措施。