不同性质铁铝土对砷酸根吸附特性的比较研究

采用批平衡法研究了8种不同性质铁铝土对砷酸根的吸附特性,分别运用Langmuir单表面方程和Langmuir双表面方程对等温吸附数据进行拟合,以较优拟合方程求出土壤对砷的最大吸附量,并采用简单线性相关分析法探讨土壤性质对砷吸附能力的影响。结果显示,铁铝土对砷吸附强烈,吸附等温线均为非线性。双表面方程对吸附等温线的拟合效果优于单表面方程。采用双表面方程预测的吸附量和实测值的决定系数(0.935～0.978)大于采用单表面方程预测获得的决定系数(0.989～0.998)。土壤的砷吸附能力可采用高能表面和低能表面两种吸附位点进行解释。采集于云南昆明的砂页岩母质发育的红壤具有最强的砷吸附能力,根据Langmuir双表面方程计算的最大吸附量为3 498 mg kg-1。土壤的砷吸附能力受到土壤中游离氧化铁、全铝、全铁、黏粒和全磷含量的显著影响,最大吸附量与这几种土壤组成与性质因子呈显著正相关关系。     

Magnetic removal/immobilization of cadmium and zinc in contaminated soils using a magnetic microparticle solid chelator and its effect on rice cultivation

Purpose

Magnetic removal techniques using functionalized magnetic nanoparticles as adsorbents have been frequently tested for use in the removal of heavy metals in aqueous solution, but seldom in farmland soil. Here, a novel magnetic microparticle solid chelator (MSC) was employed as the adsorbent for magnetic removal and/or immobilization of Cd and Zn in a paddy soil (PS), an upland soil (US), and a paddy–upland rotation soil (RS) with different degrees of pollution.

Materials and methods

MSC was applied to 14 kg air-dried soil samples (PS, US, and RS) at the dosage of 1% (w/w), and then watered, and intermittently stirred. Finally, the MSC–metal complexes were retrieved using a magnetic device (MCR treatment) or not (MC treatment), and the removal efficiency of soil Cd and Zn in MCR treatment was evaluated. After magnetic separation of MSC–metal complexes, pot experiments were performed to investigate the impacts of the magnetic remediation process on rice growth, the phytoavailability of soil Cd and Zn, and the accumulation of Cd and Zn in rice plants.

Results and discussion

The MCR treatment exhibited recovery rates of 55.4%, 49.6%, and 19.0% for MSC–metal complexes in PS, US, and RS, respectively, which brought about removal efficiencies of 2.2–12.2% for Cd and 1.9–4.6% for Zn. The MC and MCR treatments substantially decreased the availability of soil Cd, but not soil Zn; this effect was more remarkable when using CaCl₂ instead of DTPA as the extractant for determination of bioavailable metals. Furthermore, the CaCl₂-extractable Cd and Zn had a more significant relationship with Cd and Zn concentrations in rice roots. The MC and MCR treatments led to dramatic reductions in rice grain Cd of 23.9–72.1% and 37.3–63.9%, respectively, in the three soils relative to the respective controls. The MC and MCR treatments also exhibited an inhibitory effects on rice grain Zn accumulation in US (10.6% and 4.3% decreases, respectively) and RS (9.3% and 19.5% decreases, respectively), but not in PS. Moreover, the grain yield was unaffected under the MCR treatment in the three soils, and significantly increased by 29.8% under the MC treatment in US.

Conclusions

Our study suggests that MSC-based magnetic remediation technique can effectively immobilize and/or remove Cd and Zn in farmland soils, decreasing their uptake by rice plants, with no adverse effects on grain yield.

     

采后硅酸钠处理对贮藏期兰州“大接杏”果实品质和挥发性风味物质的影响

本文以兰州“大接杏”（Armeniaca vulgaris Lam. cv. Lanzhou Dajie）为试材,使用硅酸钠（10 mM）化学诱抗处理,以探讨其对杏果实品质,特别是挥发性风味物质的影响。结果表明,硅酸钠处理可延缓果实硬度、可滴定酸、可溶性固形物（SSC）和Vc含量的下降,但对果实总糖含量的影响不显著。采用固相微萃取（SPME）结合气相色谱质谱联用（GC-MS）的方法分离鉴定了“大接杏”果实的香气成份,共分离鉴定出超过100多种挥发性成份。硅酸钠处理样挥发性物质的释放总量低于对照,同时处理后的杏果还表现出醛类物质、萜类物质和β-紫罗兰酮的释放增大和脂类物质的释放减少的现象。     

农机链传动的可靠性设计

按照农机链工况的特点，提出了对农机链传动进行可靠性设计时的前提条件，论证了以链条疲劳可靠性作为链传动可靠性评定指标的理由，选定了具体进行链传动可靠性计算的方法。文中首次为读者提供了计算链传动可靠性的实例。     

Contributions of biotic and abiotic processes to the presence of an aggregate hierarchy in three different mineral soils in an experimental incubation study

Journal of Soils and Sediments - This study aims to investigate the presence of aggregate hierarchy during the decomposition of rice straw in a subtropical soil (Ultisol) with large quantities of...     

Effect of Inoculation Rhizobium and Response of Soybean-Rhizobium System to Insoluble Phosphate

In order to produce efficiently symbiotic system in acid soils which could be used for the recovery of insoluble phosphate soil and improvement of the fertility,etc.,host range of Rhizobium was isolated from the root nodules of wild and cultivated soybean varieties growing in south China,evaluated the effects of Rhizobium on enhance nitrogen fixing activities,phosphorus(P),nitrogen (N)uptakes,growth and yield of soybean under pot and field conditions.The results showed that combined Rhizobium inoculation was more effective than individual Rhizobium inoculation. The combined Rhizobium of CW54 strains had the highest effect, nodule number, nodule weight and nodule nitrogenase activity were markedly stimulated as compared to those of the control U110, respectively. The nitrogen contents in the plants treated with CW54 strains were significantly increased by 43.2% as compared to those of the control U110 in Al-P soil, but statistical significance was not observed in Fe-P soil. By contrast, inoculation with CW54 significantly enhanced phosphorus uptake of plant in Fe-P soil than that in Al-P soil. The effects of inoculation of CW54 strains in a field condition were similar to those of in a pot condition. The total biomass and yield in the plants treated with CW54 strains were significantly increased by 86.4% and 51.4% as compared to those of the control at the time of soybean podding in a field condition, respectively.These results suggested that inoculation Rhizobium was beneficial for soybean nutrient uptake,growth and yield under insoluble phosphate soil conditions.     

配制酒中苋菜红和胭脂红的测定方法

根据配制酒的加工工艺和成分含量,依据合成色素国家标准的检测方法,就其前处理和测试条件提出改进方案并加以优化,使分析结果准确,工作效率提高。     

发展专业合作社对棉花产业进步的作用探讨

近五年来中国棉花产业一直徘徊不前.其具体表现为:一是受植棉面积限制,常年国产棉花自给率连年不足70%,仍需依赖进口.二是棉花质量水平持续不前.国产棉花异性纤维含量偏高,纤维整齐度差,在生产、销售与加工中混等混级现象严重,不能完全满足纺织工业的需求.三是植棉面积年度间起伏较大,生产规模逐年减小,植棉效益低.四是棉纺企业生产成本快速递增,制约了棉花生产的发展.五是棉花栽培技术滞后,对棉花生产的技术培训、生产观摩、生产总结、信息交流等软投入愈加淡化,缺乏最前端的栽培技术支撑等.如