农村秸秆综合利用对策

阐述了秸秆综合利用途径，对秸秆焚烧原因进行了分析，提出了解决的对策和措施。     

农作物秸秆综合利用技术探讨

针对农作物秸秆焚烧的环境污染问题，提出综合利用秸秆，将秸秆通过造粒、挤出、模具成型、真空定型、牵引、定长等工艺，生产PVC木塑板，具有良好的经济效益、环境效益和社会效益。     

小麦秸秆对硝基苯的吸附能力研究

采用小麦秸秆处理硝基苯污水，通过吸附试验，利用紫外分光光度计，研究了小麦秸秆在不同条件下对吸附硝基苯性能的影响。结果表明，小麦秸秆对硝基苯的吸附，在82h后能达到90％的去除率；溶液的pH值在6～7之间有利于吸附。这为小麦秸秆的综合利用，提高农副产品的价值及解决环境污染提供了一条途径。     

油菜秸秆直接液化为液体油工艺探讨

为了实现油菜秸秆的综合利用,将其在高温高压下催化液化制备液体油。结果表明:(1)油菜秸秆中的纤维素、半纤维素、木质素质量分数分别为25.45%、11.57%、28.73%,木质素最高,其次是纤维素。(2)油菜秸秆和残渣元素分析可知,液化反应前后油菜秸秆各元素含量无明显变化,热值(HHV)分别为10.58、10.47MJ/kg。(3)硫酸盐催化作用优于氯化物催化剂,硫酸铁和硫酸亚铁在中性反应溶剂条件下催化效果较佳,特别是在酮类反应溶剂中。在实验条件为固液比1.0∶19.3(油菜秸秆与混合溶剂的质量比)、反应时间4h、催化剂用量1%(质量分数)、丙酮作反应溶剂、硫酸铁作催化剂时,转化率可达47.106%。(4)预先将油菜秸秆浸泡在1%(质量分数)KOH溶液中12h,对生物质中纤维素、半纤维素和木质素有溶胀作用,能提高转化率。(5)通过热重(TG)/差热(DTG)曲线分析,残渣的燃烧反应性更好,活化能略低于油菜秸秆。     

南林大专家发明农作物秸秆利用新技术

南林大张齐生院士课题组发明利用农作物秸秆制备秸秆炭、秸秆醋液、秸秆煤气新技术,为秸秆的高效资源化利用开辟了新途径,对推进农业生态建设具有重要意义。该课题组从农作物秸秆中提取出了秸秆炭、秸秆醋液、秸秆煤气,并设计制造了农作物秸秆碳化设备。实验证明,采用该设备处理农作物秸秆,每100公斤秸秆能够产生30公斤秸秆炭、50公斤秸秆醋液、18公斤秸秆煤气,秸秆炭是优良的土壤改良剂,能够提高农作物的产量和质量。秸秆醋液是一种绿色的农业生产     

不同镉污染农田土壤上秸秆和炭化秸秆分解动态及其对土壤镉的吸附特征

通过温室土壤培养实验，研究不同镉污染农田土壤上不同的作物秸秆和炭化作物秸秆还田后的分解动态和还田秸秆材料对污染土壤中镉的吸附特征，探讨秸秆和炭化秸秆还田做为重金属镉污染农田土壤修复剂的可行性。实验结果表明，还田的油菜秸秆和玉米秸秆在2种镉污染水稻土壤上6个月分解了43％-65％，秸秆炭化后还田则很稳定，2种镉污染土壤上还田6个月时累计分解量小于5％。2种镉污染土壤上还田的秸秆和炭化秸秆随还田时间延长镉含量逐渐增加。模拟镉污染土壤上，相同时期油菜秸秆中镉含量显著高于玉米秸秆，油菜秸秆炭中镉含量显著高于玉米秸秆炭。在镉污染土壤上，还田的玉米秸秆、油菜秸秆、玉米秸秆炭和油菜秸秆炭对土壤镉的净吸附量相近，均小于1．1μg／g。在模拟镉污染土壤上还田的油菜秸秆和油莱秸秆炭对土壤镉净吸附量最高分别达到2．74μg／g和7．03μg／g，分别是玉米秸秆和玉米秸秆炭的2倍，且显著高于其在镉污染土壤上的净吸附量，具有高的吸附能力。     

基于生命周期能值分析的秸秆能源化利用方式的对比评价

在生命周期的理论框架下,采用能值分析方法对2种秸秆能源化利用方式(秸秆直燃发电与秸秆燃料乙醇)的能值消耗、环境影响和经济效益进行了对比评价。结果表明:在秸秆直燃发电系统中,种植阶段能值投入占总能值投入的61.92%,远大于收储运输阶段和生产阶段;在秸秆燃料乙醇系统中,种植阶段和生产阶段所占比例较大,分别为45.26%和45.78%;秸秆直燃发电系统的CO2排放指标略小于秸秆燃料乙醇系统,远小于燃煤发电系统,因此,发展秸秆直燃发电和秸秆燃料乙醇对减少温室气体排放具有积极的意义;与秸秆燃料乙醇系统相比,秸秆直燃发电系统具有较高的能值产出率、可再生性和环境可持续性,较低的能值转换率和环境负载率,说明秸秆直燃发电系统综合效益优于秸秆燃料乙醇;秸秆直燃发电系统与秸秆燃料乙醇系统的可持续性指标均小于1,都不具有长期的可持续性。     

以农作物秸秆固定化混合菌去除原油

农业废弃物作为一种高效、低成本、可再生的载体,可利用其固定细菌来吸附降解石油。选取典型的农业废弃物玉米秸秆和稻草秸秆作为混合降解菌的载体,研究其对原油的降解效果。结果表明:稻草秸秆固定化菌的去除率达到90%~95%,玉米秸秆固定化菌的去除率为95%~98%,都比单纯的游离菌群G8提高了近40%;玉米秸秆固定化菌对原油的去除率比载体与菌群的简单混合物提高近了25%。比较经灭菌和不灭菌的秸秆为载体对原油的去除率,发现未经灭菌处理的秸秆对原油的去除效果更好。SEM及降解实验进一步表明玉米秸秆为较佳的载体,以玉米秸秆固定化菌3 d对原油的去除率可达到93.81%。     

3种农业废弃物处置水面溢油研究

用小麦秸秆、玉米秸秆和木屑作为吸油材料对0#柴油进行吸附研究,比较3种农业废弃物在纯油、油水样中的吸附性能及漂浮性能,并采用正交实验对影响3种农业废弃物除油率的因素条件进行了优化.结果表明:(1)小麦秸秆、木屑和玉米秸秆对柴油的吸附速率都很快,无论是在纯油中,还是在油水样中,5 min即可达到吸附饱和状态.在纯油中,小麦秸秆饱和吸油量最大,为8.54 g/g;木屑次之,为8.20 g/g;玉米秸秆饱和吸油量最小,为7.03 g/g.在油水样中,小麦秸秆饱和吸油量最大,为8.54 g/g;木屑次之,为8.08 g/g;玉米秸秆饱和吸油量最小,为7.02 g/g.(2)振荡使得小麦秸秆、木屑和玉米秸秆漂浮性能都出现明显下降,它们的漂浮率依次为小麦秸秆＞木屑＞玉米秸秆.(3)在振荡频率为0 r/min、投加量为0.9g、油膜厚度为0.55 mm的条件下,玉米秸秆和木屑粒径为830～1 700 μm、小麦秸秆粒径为500～830 μm时,除油效果最佳.     

腐秆剂对水稻秸秆腐解性能的影响

以水稻秸秆为代表性秸秆,研究了腐秆剂对秸秆腐解性能的影响。对秸秆中施用腐秆剂后各项基本指标(腐解率,C/N)进行测定,探索了不同时间、腐秆剂用量、p H、温度、含水量和尿素用量对秸秆腐解的影响。对腐解前后的秸秆进行了红外光谱(IR)分析。结果表明,秸秆在腐解25 d后速率趋于平缓;腐解的适宜p H为7.0、温度为30℃、含水量为80%、尿素用量和腐秆剂用量均为秸秆质量的1%,此条件下腐解25 d,腐解率可达40.73%。对比腐解前后秸秆的红外谱图发现,腐解后的秸秆中纤维素、木质素和半纤维素等碳水化合物发生分解,使羟基和亚甲基基团减少,同时也表明酚类化合物被氧化成醌类物质;秸秆中的蛋白质和氨基酸分解后生成酰胺类化合物、硝酸盐和铵盐。     

Occurrence and determination of organic oxidants in rivers and wastewaters

Two iodometric methods for the concentration and analysis of water samples containing organic oxidants were applied to rivers and wastewaters in Illinois, Delaware, and Pennsylvania. Oxidant concentrations detected were as high as 2.5 § 10⁻⁵ M; the methods were capable of detecting as little as 10⁻⁸ M. Compounds possibly responsible for the observed oxidizing activity include N-chloro compounds, organic peroxides, or quinones.     

Simulated and experimental evaluation of factors affecting the rate and extent of reductive dehalogenation of chloroethenes with glucose

Carbohydrates such as molasses are being added to aquifers to serve as electron donors for reductive dehalogenation of chloroethenes. Glucose, as a model carbohydrate, was studied to better understand the processes involved and to evaluate the effectiveness for dehalogenation of different approaches for carbohydrate addition. A simulation model was developed and calibrated with experimental data for the reductive dehalogenation of tetrachloroethene to ethene via cis-1,2-dichloroethene. The model included fermentors that convert the primary donor (glucose) into butyrate, acetate and hydrogen, methanogens, and two separate dehalogenator groups. The dehalogenation groups use the hydrogen intermediate as an electron donor and the different haloethenes as electron acceptors through competitive inhibition. Model simulations suggest first that the initial relative population size of dehalogenators and H(2)-utilizing methanogens greatly affects the degree of dehalogenation achieved. Second, the growth and decay of biomass from soluble carbohydrate plays a significant role in reductive dehalogenation. Finally, the carbohydrate delivery strategies used (periodic versus batch addition and the time interval between periodic addition) greatly affect the degree of dehalogenation that can be obtained with a given amount of added carbohydrate.     

Combined effects of soil moisture and carbaryl to earthworms and plants: simulation of flood and drought scenarios

Studying tolerance limits in organisms exposed to climatic variations is key to understanding effects on behaviour and physiology. The presence of pollutants may influence these tolerance limits, by altering the toxicity or bioavailability of the chemical. In this work, the plant species Brassica rapa and Triticum aestivum and the earthworm Eisenia andrei were exposed to different levels of soil moisture and carbaryl, as natural and chemical stressors, respectively. Both stress factors were tested individually, as well as in combination. Acute and chronic tests were performed and results were discussed in order to evaluate the responses of organisms to the combination of stressors. When possible, data was fitted to widely employed models for describing chemical mixture responses. Synergistic interactions were observed in earthworms exposed to carbaryl and drought conditions, while antagonistic interactions were more representative for plants, especially in relation to biomass loss under flood-simulation conditions.     

氟石膏中氟的分布及固氟脱酸改性

以工业副产物氟石膏为研究对象,通过筛分进行粒度分析,得到不同粒径pH值、水溶性氟以及总氟含量的变化规律;重点研究了掺入2种碱性工业副产物作为改性剂对氟石膏化学改性固氟脱酸的效果,从而确定改性剂的最佳掺量。结果表明,氟石膏中氟的分布有一定规律;掺加5%的电厂干法脱硫灰或2%钢铁厂烧结烟气脱硫灰能很好的起到固氟脱酸的效果。     

Toxicity and biodegradation of diamines

Phytotoxicity and cytotoxicity of 2,4-diaminotoluene (2,4-D), 4,4'-methylenedianiline (4,4-D), and 1,6-hexanediamine (1,6-D) were investigated by observing the germination of young radish seeds and the viability of HeLa cells, respectively. 2,4-D showed the highest, 4,4-D intermediate, and 1,6-D lowest cytotoxicity. However, the phytotoxicity decreased in the order of 4,4-D > 2,4-D > 1,6-D. Contrary to the results previously reported, in the modified Sturm test the activated sludge degraded 2,4-D and 4,4-D as well as 1,6-D without any pre-acclimation. Ochrobacterium antropi was isolated for degradation of 2,4-D and 4,4-D and Pseudomonas citronellolis for 1,6-D degradation. Thielevia sp. was isolated as 2,4-D degrading fungus and Aspergillus sp. as 4,4-D and 1,6-D degrading fungus. The fungi degraded the diamines faster than the bacteria.     

四氯化碳的生产与应用及其淘汰策略

四氯化碳是一种消耗臭氧层物质,其生产和消费都面临着严峻的淘汰形势.简要叙述了四氯化碳的生产技术,以四氯化碳为原料生产大宗化学品和精细化学品的转化技术,四氯化碳作为化工助剂在我国的应用情况以及相应的淘汰方法和技术进展.     

The effect of ambient ozone pollution and acidic rain on the growth and chlorophyll content of green and white ash

Two- and three-year old green ash (Fraxinus americana L.) and white ash (Fraxinus pennsylvanica Marsh.) seedlings were exposed to combinations of ambient ozone and acidic ambient rainfall in New Brunswick, New Jersey. During the 3-year study the potted seedlings did not develop typical foliar ozone toxicity symptoms, despite the occurrence of as many as 78 h in exceedance of the National Ambient Air Quality Standard of 0.12 ppm. Although the pH of the rainfall was as low as 3.6 and averaged 4.1, no symptoms were observed resulting from the ambient precipitation. The rate of shoot growth in terms of height and diameter was generally not affected by either of the pollutants during the growing season. Although the chlorophyll content of white ash foliage was low following frequent rainfall in the early summer of 1984, there was no statistically significant evidence that acid raid or ambient ozone decreased chlorophyll in ash seedlings during the 3-year study.     

Decomposition and mineralization of cefaclor by ionizing radiation: kinetics and effects of the radical scavengers

There has been recent growing interest in the presence of antibiotics in different environmental sectors. One considerable concern is the potential development of antibiotic-resistant bacteria in the environment, even at low concentrations. Cefaclor, one of the beta-lactam antibiotics, is widely used as an antibiotic. Kinetic studies were conducted to evaluate the decomposition and mineralization of cefaclor using gamma radiation. Cefaclor, 30 mg/l, was completely degraded with 1,000 Gy of gamma radiation. At a concentration of 30 mg/l, the removal efficiency, represented by the G-value, decreased with increasing accumulated radiation dose. Batch kinetic experiments with initial aqueous concentrations of 8.9, 13.3, 20.0 and 30.0mg/l showed the decomposition of cefaclor using gamma radiation followed a pseudo first-order reaction, and the dose constant increased with lower initial concentrations. At a given radiation dose, the G-values increased with higher initial cefaclor concentrations. The experimental results using methanol and thiourea as radical scavengers indicated that ()OH radicals were more closely associated with the radiolytic decomposition of cefaclor than other radicals, such as e(aq)(-) or ()H. The radical scavenger effects were tested under O(2) and N(2)O saturations for the enhancement of the TOC percentage removal efficiencies in the radiolytic decomposition of cefaclor. Under O(2) saturation, 90% TOC removal was observed with 100,000 Gy. Oxygen is well known to play a considerable role in the degradation of organic substances with effective chain reaction pathways. According to the effective radical reactions, the enhanced TOC percentage removal efficiencies might be based on the fast conversion reactions of e(aq)(-) and ()H with O(2) into oxidizing radicals, such as O(2)(-) and HO(2)(), respectively. 100% TOC removal was obtained with N(2)O gas at 20,000 Gy, as reducing radicals, such as e(aq)(-) and ()H, are scavenged by N(2)O and converted into ()OH radicals, which have strong oxidative properties. The results of this study showed that gamma irradiation was very effective for the removal of cefaclor in aqueous solution. The use of O(2) or N(2)O, with radiation, shows promise as effective radical scavengers for enhancing the TOC or COD removal efficiencies in pharmaceutical wastewaters containing antibiotics. However, the biological toxicity and interactions between various chemicals during the radiolytic treatment, as well as treatments under conditions more representative of real wastewater will require further studies.     

Strategies of maintaining the natural purification potential of rivers and lakes

Surface waters have a great impact on ecology and life of man. Because of their current use and exploitation, chemical and biological pollution, as well as physical changes of rivers and lakes are common. Natural self-purification potential helps to compensate harms to a certain degree. Proposals are given to detect restrictions of the purification potential in time as well as to support and to enhance the natural purification potential.     

Decomposition of 14C-fenitrothion under the influence of UV and sunlight under tropical and subtropical conditions

The decomposition of (14)C-fenitrothion on silica gel chromatoplates as well as in polar and non polar solvents under sunlight and ultraviolet light was investigated, Its stability to sunlight on leaf surfaces of bean plants and on different surfaces (such as glass, quartz and plastic) was also determined. The main photoproducts were identified as carboxyfenitrothion, fenitrooxon, carboxyfenitrooxon and 3-methyl-4-nitrophenol and a small amount 3-caboxy-4-nitrophenol and methyl parathion. The addition of carbaryl and deltamethrin insecticides slightly accelerated the photodecomposition of fenitrothion on silica gel plates and in solution.