磁性壳聚糖凝胶微球对水中Pb(Ⅱ)的吸附性能

以壳聚糖为原材料,通过原位共沉淀法和柠檬酸钠交联法制备了一种新型多孔磁性壳聚糖凝胶微球吸附剂CS-citrate/Fe₃O₄.利用扫描电镜（SEM）、透射电镜（TEM）、傅里叶红外光谱（FTIR）、热重分析（TG）对吸附剂进行了表征.结果表明,吸附剂内部具有发达的孔隙结构,并均匀分布有平均直径为（4.79±1.09）nm的Fe₃O₄纳米颗粒;吸附剂中引入Fe₃O₄后,仍存在羟基、氨基和羧基等功能基团,且吸附剂磁性良好可用于磁场分离;吸附剂对Pb（Ⅱ）的吸附等温线和动力学研究表明,吸附过程以化学吸附为主,最大吸附容量可达178.25mg/g.     

热带树木燃烧颗粒物中脱水糖和醋菲烯的排放特征

森林植被燃烧是大气颗粒物的重要来源之一.为研究生物示踪物,对22种东南亚典型热带树木进行开放式燃烧实验,这些树木主要可分为常绿乔木、落叶乔木和灌木这3大类.分析植被燃烧产生的脱水糖、醋菲烯(acephenanthrylene)、醋蒽烯(aceanthrylene)、惹烯等生物质燃烧示踪物的排放因子特征.22种典型东南亚热带树木燃烧产生的颗粒物中3种植物类型的总糖平均排放因子大小趋势为:常绿乔木(1.56 g·kg~(-1)±1.01 g·kg~(-1))灌木(1.99 g·kg~(-1)±0.64 g·kg~(-1))落叶乔木(5.38 g·kg~(-1)±7.18 g·kg~(-1));醋菲烯平均排放因子趋势为常绿乔木(2.63 mg·kg~(-1)±2.44 mg·kg~(-1))≈灌木(2.46 mg·kg~(-1)±2.14 mg·kg~(-1))落叶乔木(6.07 mg·kg~(-1)±8.50 mg·kg~(-1)).关于示踪物特征比率,乔木、灌木的左旋葡聚糖(Lev)/甘露聚糖(Man)平均值分别为20.6±11.9、23.2±9.20,总范围为5.80~51.5;两者的醋菲烯(AP)/醋蒽烯(AC)平均值分别为7.13±5.18、5.53±1.51.相较于受影响条件较多的脱水糖,芳烃类化合物分析方法简捷,其中AP/AC虽然较荧蒽(FL)/芘(PY)的稳定性略差,但受到的其他污染源干扰少、特异性高.因此,在生物质源解析方面可以综合考虑各示踪物的优缺点以提高准确性,其中醋菲烯是作为生物示踪物的较优选择.     

白云石的硫化氢高温脱除性能研究

用天然白云石制备了半焙烧白云石和全焙烧白云石，并在固定床上对这些白云石进行硫化氢的高温脱除性能研究，同时考察了反应温度、空速、粒子粒径对白云石脱硫性能的影响。用X射线衍射（XRD）、热重分析（TG）和气体吸附等测试手段，对脱硫剂的物相组成、结构、比表面积和孔容进行了表征。结果表明，白云石是一种很好的吸硫剂。在同样条件下，3种白云石中半焙烧白云石具有最好的脱硫效果；而对于同一种白云石，反应条件的差异也会导致其脱硫效果的变化。白云石的脱硫性能与其微观结构有密切关系。     

水温与营养值对水库藻华态势的影响

主要研究了水温和营养值在大沙河水库绿藻、硅藻藻华生物量的影响；提出了用营养值来定量描述水体的富营养状态；通过构筑一定形式的辅助变量，分别提出了在水温20℃和30℃条件下藻华生物量的预测模型；进一步阐述了水温对藻生长态势的影响原理。研究表明水温一方面影响藻生命活动的活性、速率，另一方面影响藻对水中营养物的利用率和自身代谢率。在水温20℃和30℃时，两方面的总体作用结果有所不同。对营养物的利用率和自身代谢率方面更大程度上影响藻华生物量的多少。     

酸沉降和大气污染对华南典型森林生态系统生物量的影响

调查酸沉降和大气污染对华南典型森林生态系统植物生物量的影响。结果发现,环境污染对树木的生长以及森林生物量影响较大。采用树干解析方法研究发现,不管是尾叶桉还是马尾松其树高、胸径和材积连年生长量基本趋势是污染地区样地比清洁区样地低。尾叶桉和马尾松林分中的生物量也是污染区样地比清洁区样地低。污染区样地中尾叶桉和马尾松林分总生物量分别为66.89t·hm-2和77.56t·hm-2,仅分别为清洁区的78.89%和94.49%。环境污染均促进这两个树种根系的生长,而抑制其干材的生长。尾叶桉和马尾松根系生物量占林木层生物量比例:污染区样地分别为65.16%和15.08%;清洁区分别为40.50%和14.48%。此两个树种干材生物量占林木层生物量比例:污染区样地分别为19.87%和57.71%;清洁区分别为38.15%和70.33%。本研究结果将为华南地区森林生态系统的保护提供科学依据。     

神经网络模型森林生物量遥感估测方法的研究

森林生物量的估测是全球变化研究的基础,而遥感宏观、综合、动态、快速的特点决定了基于遥感的生物量模型为森林生物量估测的发展方向,目前的遥感生物量估测方法大多基于回归分析,需要预先假设、事后检验,仅为经验性的统计模型。神经网络的分布并行处理、非线性映射、自适应学习和容错等特性,使其具有独特的信息处理和计算能力,在机制尚不清楚的高维非线性系统体现出强大优势,可以用于遥感生物量估测。文章在野外调查的基础上,尝试应用BP网络和RBF网络技术,建立广州TM遥感影像数据与森林样方生物量实测数据之间的神经网络模型,通过训练和仿真,与生物量实测数据进行比较。结果表明,在独立样地估测中,人工神经网络估测的相对误差均小于15.18%,获得了满意的效果。而RBF网络与BP网络相比,在识别精度上、稳定性、速度上,均优于BP网络,其最大相对误差不超过10.12%,平均相对误差为4.76%。可见应用神经网络方法的“黑箱”操作虽然难以归纳出指导性规律,但可以获得很高的精度。尤其RBF网络,在训练完成后,可以应用该模型进行大区域生物量估算,对于森林的规划及管理具有深远意义。     

Influence of iron, nickel and cobalt on biogas production during the anaerobic fermentation of fresh residual biomass

We have investigated the dependence of the rate of the production of biogas upon the concentration of nickel, cobalt and iron at sub-toxic concentration and monitored its composition as amount of hydrogen, methane and carbon dioxide. The distribution of the added metals between the liquid and solid phase has also been monitored.

The results of our investigations show that the addition of any of the listed metals to the sludge may cause the production of a higher amount of biogas and influence the methane or carbon dioxide percentage. Conversely, the effect on the hydrogen production depends upon the metal added, the age of the active sludge used, and its adaptation to the susbtrate. As a general feature, during the acidogenesis phase, nickel reduces, while iron increases, the percentage of dihydrogen in the biogas, while cobalt has no influence.     

Copper, Lead and Zinc Mobility and Bioavailability in a River Sediment Contaminated with Paint Stripping Residue

A river embankment sediment beneath a road bridge in South Australia had been surveyed on a previous occasion to a depth of 10 cm and found to contain high levels of copper, lead and zinc deposited during previous lead and zinc-based primer paint stripping operations prior to repainting the bridge. Since the river embankment is geologically different from the surrounding non-embankment soils, and a sufficient distance from the bridge along the river embankment could not be traversed, the geological background Cu, Pb and Zn fraction was established initially using a solid phase sequential extraction (SPSE) procedure. Assessment of the degree of contamination and extent of vertical mobility was then established. Copper was a minor contaminant and present predominantly as the geological background species. Lead was partitioned evenly between the oxalate soluble fraction and residual fraction to a depth of 30 cm with a decrease in total Pb concentration from 497 to 141 mg Pb kg^–1 while Zn was predominantly in the oxalate soluble fraction to a depth of 15cm with a decrease in concentration from 1013 to 150 mg Zn kg^–1. The reduced rate of nitrification and the lower total concentration of NO₃ ^–-N together with the higher respiratory quotient, combined with the lower microbial quotient, are indicative of microbial stress due to heavy metal toxicity. In the case of Pb and Zn paint stripping residues, these changes in indicators of microbial health are possibly the result of the greater abundance and hence possible bioavailabilty of organo- and chloro-Pb compared to organo- and chloro-Zn complexes.     

Carbon Sequestration by Carbonization of Biomass and Forestation: Three Case Studies

We proposed the carbon sink project called “Carbon Sequestration by Forestation and Carbonization (CFC),” which involves biomass utilization and land conservation by incorporating the products of biomass carbonization into the agents for soil improvement, water purification, etc. Our purpose was to demonstrate the potential of the CFC scheme for carbon sequestration, particularly carbon storage in soil. Case studies were conducted in both developing and developed countries. 1. In southern Sumatra, Indonesia, 88,369 Mg-C year⁻¹ of wood residue from a plantation forest and excess bark from a pulp mill would be converted into 15,571 Mg-C year⁻¹ of the net carbon sink by biochar for soil improvement. The fixed carbon recovery of the system is 21.0%. 2. In a semiarid region in western Australia, the carbonization of wood residue was incorporated with multipurpose projects of a mallee eucalyptus plantation that involved the function of salinity prevention. During the project period of 35 years, the total carbon sink would reach 1,035,450 Mg-C with 14.0% by aboveground biomass, 33.1% by belowground biomass and 52.8% by biochar in soil. 3. In southern Kyushu, Japan, the study was focused on the effective use of surplus heat from a garbage incinerator for carbonizing woody materials. Sawdust of 936.0 Mg-C year⁻¹ would be converted into the net carbon sink of 298.5 Mg-C year⁻¹ by carbonization, with the fixed carbon recovery of the system being 31.9%. Consequently, the CFC project could encourage the creation of a carbon sink in soil. However, we recognize that the quality standard of biochar, the stability of biochar in soil, and the methods for monitoring biochar utilization must be clarified before incorporating biochar carbon into the carbon credit system. Throughout this article (except for diagrams and in citation details) carbonized biomass is, with the authors'agreement, called ‘biochar’ in lieu of the commonly used but misleading word ‘charcoal’ (Editor).     

旋转锥式闪速热解生物质试验研究

利用旋转锥式闪速热解装置,对生物质进行了闪速热解试验研究。生物质是一种可再生的能源,在无氧或有限氧气供给的条件下热解为液体、固体、气体3种燃料产品。介绍了以旋转锥式反应器为核心的闪速热解液化设备、工艺参数及产物特性,并根据此结果对比了常规热解、快速热解、闪速热解的生物油典型数据,为生物质废弃物的有效清洁利用及可再生能源的生产探索了新的途径。