Strategies for improving the photocatalytic performance of metal-organic frameworks for CO2 reduction: A review

Photocatalytic CO₂ reduction is an appealing strategy for mitigating the environmental effects of greenhouse gases while simultaneously producing valuable carbon-neutral fuels. Numerous attempts have been made to produce effective and efficient photocatalysts for CO₂ reduction. In contrast, the selection of competitive catalysts continues to be a substantial hindrance and a considerable difficulty in the development of photocatalytic CO₂ reduction. It is vital to emphasize different techniques for building effective photocatalysts to improve CO₂ reduction performance in order to achieve a long-term sustainability. Metal-organic frameworks (MOFs) are recently emerging as a new type of photocatalysts for CO₂ reduction due to their excellent CO₂ adsorption capability and unique structural characteristics. This review examines the most recent breakthroughs in various techniques for modifying MOFs in order to improve their efficiency of photocatalytic CO₂ reduction. The advantages of MOFs using as photocatalysts are summarized, followed by different methods for enhancing their effectiveness for photocatalytic CO₂ reduction via partial ion exchange of metal clusters, design of bimetal clusters, the modification of organic linkers, and the embedding of metal complexes. For integrating MOFs with semiconductors, metallic nanoparticles (NPs), and other materials, a number of different approaches have been also reviewed. The final section of this review discusses the existing challenges and future prospects of MOFs as photocatalysts for CO₂ reduction. Hopefully, this review can stimulate intensive research on the rational design and development of more effective MOF-based photocatalysts for visible-light driven CO₂ conversion.     

污染土壤添加有机物质对黑麦草吸收铜的影响

研究了泥炭和堆肥对铜污染土壤盆栽黑麦草吸收铜状况的影响。结果表明 ,黑麦草地上、地下部含铜量皆随土壤污染水平提高而增加 ,地下部的增幅远大于地上部 ;添加有机物质明显降低了黑麦草地上、地下部的含铜量 ,平均降幅近 3 0 %。泥炭降低黑麦草地上、地下部含铜量的作用随土壤污染水平的提高而逐渐变小 ,而堆肥的作用至重度污染水平仍较明显 ;在近 4 0 0mg/kg铜污染水平上 ,有机物质表现出最佳降低植株铜吸收量的效果。有机物质的控制作用与土壤pH有关 ,并在 3茬黑麦草的试验期间内得以维持     

侧吸导烟技术的经济性分析

介绍了侧吸导烟技术的技术背景,分析计算了焦炉装煤烟尘成分及含量,经对该技术的经济效益进行概算后显示,该技术可以有效改善焦炉区及周边环境,每年还可创造可观的经济效益,是一项值得研究推广的技术。     

Heavy metal bioaccumulation in selected medicinal plants collected from Khetri copper mines and comparison with those collected from fertile soil in Haridwar,India

Heavy metal distribution in medicinal plants is gaining importance not only as an alternative medicine, but also for possible concern due to effects of metal toxicity. The present study has been focused on emphasizing the heavy metal status and bioaccumulation factors of V, Mn, Fe, Co, Cu, Zn, Se (essential metals) and Cr, Ni, Cd, As and Pb (potentially toxic metals) in medicinal plants grown under two different environmental conditions e.g., near to Khetri copper mine and those in fertile soils of Haridwar, both in India, using Instrumental Neutron Activation Analysis (relative method) and Atomic Absorption Spectrometry. The copper levels in the medicinal plants from Khetri were found to be 3-4 folds higher (31.6–76.5 mg kg^?1) than those from Haridwar samples (7.40–15.3 mg kg^?1), which is correlated with very high copper levels (763 mg kg^?1) in Khetri soil. Among various heavy metals, Cr (2.60–5.92 mg kg^?1), Cd (1.47–2.97 mg kg^?1) and Pb (3.97–6.63 mg kg^?1) are also higher in concentration in the medicinal plants from Khetri. The essential metals like Mn (36.4–69.3 mg kg^?1), Fe (192–601 mg kg^?1), Zn (24.9–49.9 mg kg^?1) and Se (0.13–0.91 mg kg^?1) and potentially toxic metals like Ni (3.09–9.01 mg kg^?1) and As (0.41–2.09 mg kg^?1) did not show much variations in concentration in the medicinal plants from both Khetri and Haridwar. The medicinal plants from Khetri, e.g., Ocimum sanctum, Cassia fistula, Withania somnifera and Azadirachta Indica were found rich in Ca and Mg contents while Aloe barbadensis showed moderately high Ca and Mg. Higher levels of Ca-Mg were found to correlate with Zn (except Azadirachta Indica). The bioaccumulation factors (BAFS) of the heavy metals were estimated to understand the soil-to-plant transfer pattern of the heavy metals. Significantly lower BAF values of Cu and Cr were found in the medicinal plants from Khetri, indicating majority fraction of these metals are precipitated and were immobilized species unsuitable for plant uptake. Overall, Withania somnifera (Ashwagandha) showed very high metal bioaccumulation.     

Intestinal absorption of the acetamiprid neonicotinoid by Caco-2 cells: Transepithelial transport,cellular uptake and efflux

The human intestinal absorption of acetamiprid (AAP) using the Caco-2 cell line reveals that AAP flux was active in a bidirectional mode with an apparent permeability coefficient of 26^.10^?6 cm·s^?1 at 37°C. Apical uptake was concentration-dependent and unsaturated for AAP concentrations up to 200 μ M. AAP cell preloading demonstrated the involvement of active transport mechanisms. Arrhenius plot analysis revealed an unusual profile with two apparent activation energies suggesting two transport processes. Uptake Vi studies indicated the involvement of a sodium-dependent transporter, the presence of a common transporter of AAP and nicotine and the involvement of Ti-sensitive ATP-dependent efflux transporters. Apical efflux investigations showed the involvement of inward active transporter(s). Whereas vincristine had no effect on intracellular accumulation, taxol and daunorubicin treatments unexpectedly led to 10% and 23% reductions respectively, suggesting that the latter shared a common inward transporter with AAP. All these results suggest full and express AAP absorption in vivo with transport involving both inward and outward, passive and active mechanisms. Thus, AAP or its metabolites could be representative of a risk for human health after its ingestion in food.     

粉煤灰处理染料废水的研究

利用粉煤灰吸附性能较好、来源广泛及价格低廉等特点,对染料废水进行吸附试验研究。结果表明,粉煤灰的活化方式、粒度及用量对染料废水吸附性能有影响。160—200目30%硫酸活化粉煤灰吸附能力最强,且对染料废水的吸附过程符合Langmuir吸附等温曲线,最大吸附量为667mg/g。     

Investigation of heavy metal contaminations in the lower Sakarya river water and sediments

In this work, water and sediment samples were collected from three different stations located along the Sakarya river between May and September 2003. Lead, copper, chromium, zinc, nickel and cadmium concentrations were determined by using solvent extraction and flame atomic absorption spectrometric method. The results show that differences based upon sampling times, regions, sediment and water samples were observed. The mean levels of copper, nickel, chromium, lead, cadmium, zinc for sediment samples are; 4.630 μg g⁻¹, 13.520 μg g⁻¹, 8.780 μg g⁻¹, 2.550 μg g⁻¹, 9.990 μg g⁻¹ and for water samples are; 0.851 μg g⁻¹, 1.050 μg g⁻¹, 0.027 μg g⁻¹, 1.786 μg g⁻¹, 0.236 μg g⁻¹, 0.173 μg g⁻¹, respectively.     

Absorption characteristics of new solvent based on a blend of AMP and 1,8-diamino-p-menthane for CO2 absorption

Aqueous 1,8-diamino-p-menthane (KIER-C3) and commercially available amine solutions were tested for CO₂ absorption. A 2-amino- 2-methyl-1-propanol (AMP) solution with an addition of KIER-C3 showed 9.3% and 31.6% higher absorption rate for CO₂ than the AMP solution with an addition of monoethanolamine (MEA) and ammonia (NH₃), respectively. The reaction rate constant for CO₂ absorption by the AMP/KIER-C3 solution was determined by the following equation: k_2,AMP/C3 = 7.702×10⁶ exp (-2248.03/T). A CO₂ loading ratio of the AMP/KIER-C3 solution was also 2 and 3.4-times higher than that of the AMP/NH3 solution and the AMP/MEA solution, respectively. Based on the experimental results, KIER-C3 may be used as an excellent additive to increase CO₂ absorption capability of AMP.     

博斯腾湖夏季水下光场特征分析及影响因素探讨

2011年8月,在新疆博斯腾湖17个站点进行水样采集,同步对11个站点进行水下光场原位测定.结果发现,博斯腾湖夏季总颗粒物吸收系数光谱表现出明显的浮游植物吸收特征,而浮游植物光谱曲线有明显的硅藻吸收光谱特征.在光合有效辐射波段,有色可溶性有机物（CDOM）吸收系数与浮游植物吸收系数对总吸收的贡献相当,而非色素颗粒物对总吸收的贡献最低.水下光谱衰减系数的最小值出现在580nm左右的绿光波段,PAR漫射衰减系数平均值为0.53m-1,平均真光层深度约为9.69m,大于湖水平均深度.在博斯腾湖虽然纯水和CDOM在总吸收中占有很重要的部分,但主导漫射衰减的因子仍为颗粒物.通过本文研究,以期能为干旱地区湖泊环境保护和水质遥感监测提供数据和理论基础.     

改进测定水中氨氮分子吸收光谱法的试验研究

水中氨氮含量是反应水质状况的重要指标。文章对测定水中氨氮气相分子吸收光谱法(标准号HJ/T195-2005)进行了改进试验研究。第一,对氧化剂的配比进行了改进,使氨氮的测定范围扩展至100μg。第二,对标准HJ/T195-2005中直接使用亚硝酸钠标准溶液做标准曲线的处理方式也做了探讨。通过一系列对比实验认为,应用硫酸铵标准溶液做工作曲线更加准确合理。最后应用改进后的气相分子吸收光谱法和纳氏比色法或滴定法对多种实际废水样品进行同时测定。结果表明,改进后的气相分子吸收光谱法测定氨氮的范围更宽,灵敏度更高和准确度更好。