Utilization of waste product (tamarind seeds) for the removal of Cr(VI) from aqueous solutions: Equilibrium, kinetics, and regeneration studies

In the present study, an adsorbent was prepared from tamarind seeds and used after activation for the removal of Cr(VI) from aqueous solutions. The tamarind seeds were activated by treating them with concentrated sulfuric acid (98% w/w) at a temperature of 150 °C. The adsorption of Cr(VI) was found to be maximum at low values of initial pH in the range of 1–3. The adsorption process of Cr(VI) was tested with Langmuir, Freundlich, Redlich–Peterson, Koble–Corrigan, Tempkin, Dubinin–Radushkevich and Generalized isotherm models. Application of the Langmuir isotherm to the system yielded a maximum adsorption capacity of 29.7 mg/g at an equilibrium pH value ranging from 1.12 to 1.46. The adsorption process followed second-order kinetics and the corresponding rate constants obtained were 2.605 × 10⁻³, 0.818 × 10⁻³, 0.557 × 10⁻³ and 0.811 × 10⁻³ g/mg min⁻¹ for 50, 200, 300 and 400 mg/L of initial Cr(VI) concentration, respectively. The regenerated activated tamarind seeds showed more than 95% Cr(VI) removal of that obtained using the fresh activated tamarind seeds. A feasible solution is proposed for the disposal of the contaminants (acid and base solutions) containing high concentrations of Cr(VI) obtained during the regeneration (desorption) process.     

Effects of Smoke Emissions from a Charcoal Kiln on the Functioning of Forest Soil Systems: A Microcosm Study

Long-term charcoal production in small private charcoal kilns (CK) in Eastern Bieszczady Mts. (SE Poland) can cause local smoke contamination of the ambient forest environment. Responses of model soil systems, contaminated or not contaminated by CK smoke, to contrasting combinations of hydrothermic regimes were compared in laboratory microcosms (respiration of soil community, decomposition rate of soil organic matter and cotton stripes, herb seeds germination were studied). The majority of the obtained data show a markedly higher level of soil biological activity in the CK versus the control series. In some cases CK and control soil systems show different patterns of reactions to the tested combinations of microclimate regime. These phenomena should at least partly be attributed to the effects of CK pollution.     

气体二氧化氯对葡萄表面细菌杀菌规律研究

研究气体二氧化氯杀灭金黄色葡萄球菌、大肠杆菌、李斯特单增菌和腐生酵母菌4种葡萄表面的危险致病菌的杀菌规律。在实验范围内,随着气体二氧化氯浓度的增加和杀菌时间的延长,杀菌效果明显增加。当杀菌时间超过12min,杀菌量级几乎不再增加。杀菌效率随温度的增加而减小,在实验温度条件下,只有大肠杆菌的杀菌效果减少了5.38～6.09log量级,其他3种菌均减少了6log量级以上,杀菌作用温度在实验条件下对杀菌效果影响不大。研究表明,当气体二氧化氯的杀菌浓度为25mgl-1、杀菌时间12min、杀菌温度25℃的条件下,金黄色葡萄球菌、李斯特单增菌和腐生酵母菌均减少了6.4log量级以上,而大肠杆菌达到5.76log量级;同时表明二氧化氯气体的杀菌保鲜功能也是食品安全技术非热杀菌手段。     

Conservation of indigenous plants to support community livelihoods: the MGU – Useful Plants Project

Through the MGU – Useful Plants Project (2007–2015) led by the Royal Botanic Gardens Kew, high-quality seed collections and research information have been gathered on useful indigenous plants selected by communities in Botswana, Kenya, Mali, South Africa, and Mexico. Local communities were trained in seed conservation, plant propagation, and planting activities, while revenue generation was promoted directly through the sustainable use of plants and plant products and indirectly through wider environmental and cultural services. The success of this project was determined by its participative approach, involving local communities in plant conservation activities and using plant research to support it. However, the promotion of sustainable use and income generation highlighted issues that confirmed the importance of using a ‘holistic approach’ to address the objective of poverty reduction and contribute to improved livelihoods in the communities.     

Herbicide residues in grapes and wine

Abstract

The persistence of several common herbicides from grapes to wine has been studied. Shiraz, Tarrango and Doradillo grapes were separately sprayed with either norflurazon, oxyfluorfen, oxadiazon or trifluralin ‐ persistent herbicides commonly used for weed control in vineyards. The dissipation of the herbicides from the grapes was followed for 28 days following treatment. Results showed that norflurazon was the most persist herbicide although there were detectable residues of all the herbicides on both red and white grapes at the end of the study period. The penetration of herbicides into the flesh of the grapes was found to be significantly greater for white grapes than for red grapes. Small‐lot winemaking experiments showed that norflurazon persisted at levels close to the initial concentration through vinification and into the finished wine. The other herbicides degraded, essentially via first‐order kinetics, within the period of “ first fermentation”; and had largely disappeared after 28 days. The use of charcoal together with filter pads, or with diatomaceous earth was shown to be very effective in removing herbicide residues from the wine. A 5% charcoal filter removed more than 96% of the norflurazon persisting in the treated wine.     

模拟酸雨对葡萄叶片和花粉的影响

以巨峰葡萄为试材,研究了模拟酸雨对叶片和花粉的影响,结果表明：（１） 经ｐＨ２ ．５ 和ｐＨ２ ．０ 的酸雨处理后叶片在短期内均出现不同程度的可见性受害伤斑,叶绿素含量和净光合速率下降．（２） 酸雨使叶片ＳＯＤ活性及不饱和脂肪酸指数（ＩＵＦＡ）下降,膜脂过氧化产物ＭＤＡ 含量及细胞膜透性显著增加,并且这些指标的变化与酸雨ｐＨ值有显著的相关性．（３）叶片对酸雨处理引起的生理伤害有一定的自我修复功能．（４） 酸雨对叶片的生长和花粉发芽有明显的抑制作用     

污染稻、麦籽实中Cd、Cu、Pb的分布及其存在形态初探

采用组织化学及溶剂提取法研究了污染水稻、小麦籽实中Cd、Cu、Pb的分布及存在形态．结果表明,3种金属元素在水稻、小麦籽实各形态结构中的浓度具有明显不均一性,胚中浓度显著高于胚乳,颖壳,皮层中浓度也较高;糙米、麦粒中的Cd、Cu、Pb在去离子水、0.1mol EDTA、1％醋酸、2.5％　NaCl、0.2％NaOH、70％乙醇中的溶出比例有显著差异;综合2项试验结果可以看出Cd、Cu、Pb在籽实中主要与谷物成分结合形成配合物,其优势形态是蛋白质结合态．     

Cd对野茼蒿种子发芽的影响

为了研究重金属Cd在野茼蒿生长初期所产生的毒性效应,本文以野茼蒿种子为实验材料,分别设定了低浓度组(0、0.2、0.5、0.8、1.0和5.0 mg·L-1)和高浓度组(0、10、25、50和100 mg·L-1)2组实验,对在Cd胁迫作用下野茼蒿种子的萌发生长进行了研究.结果表明:在低浓度(＜5 mg·L-1)下,C...     

1,4-二氯苯对小白菜种子萌发和幼苗的毒性

采用室内模拟染毒法,研究1,4-DCB(1,4-二氯苯)对3种小白菜种子(矮青6号、上海青和秦白2号)萌发和蔬菜幼苗的毒性作用. 结果表明:1,4-DCB作用后,3种小白菜种子的发芽势、种子发芽率、发芽指数和活力指数均降低,并呈现一定的剂量-效应关系;种子受1,4-DCB胁迫后,小白菜幼苗的根和苗生长都受到了抑制,根长和苗高降低,根苗比显著下降;随着ρ(1,4-DCB)的升高,受胁迫后的幼苗叶片的w(游离脯氨酸)呈现先升高后降低的趋势,而MDA(丙二醛)含量逐渐升高,与ρ(1,4-DCB)呈正相关;幼苗叶片SOD(超氧化物歧化酶)活性在ρ(1,4-DCB)为5 mg/L时升高,在ρ(1,4-DCB)为10和50 mg/L时明显降低;与对照组相比,各处理组幼苗叶片POD(过氧化物酶)活性均升高,但是ρ(1,4-DCB)为50mg/L时酶活性比ρ(1,4-DCB)为10 mg/L时下降. 表明水体中1,4-DCB污染对蔬菜种子萌发和幼苗生长产生毒性,其毒性机制与膜脂质过氧化有关.