Bauxite residue (red mud) increases phosphorus retention in sandy soil catchments in Western Australia

The Peel-Harvey estuary on the Swan Coastal Plain, Western Australia has become eutrophic partly because of the leaching of fertiliser phosphorus from sandy soils. The acid, coarse textured sandy soils are predominantly quartz, have a low iron and aluminium content and do not retain phosphorus. Red mud, derived from bauxite, is a by-product of the alumina industry and has the ability to retain phosphorus. Retention of phosphorus is enhanced when the red mud is neutralised with gypsum. Red mud has been suggested as a soil amendment to reduce phosphorus leaching.To investigate the reduction in the leaching of phosphorus from soils amended with red mud, weirs were constructed at the outlets from a pair of catchments to quantify the amount of phosphorus in the streamflow. Both catchments were deep grey Bassendean sand. One of the catchments was treated with 80 t/ha of red mud which had been neutralised with waste gypsum from the phosphate industry. The red mud was applied to the soil surface using conventional fertiliser spreading equipment. The other catchment was untreated.The red mud reduced phosphorus loss by 70% from 13.8 kg/ha on the untreated catchment, to 4.2 kg/ha on the treated catchment. Both catchments were treated with 20.4 kg/ha of phosphorus as superphosphate. The catchment treated with red mud also received a further 41.5 kg/ha of phosphorus from the phosphogypsum that was used to neutralise the red mud.Our results show that red mud reduces phosphorus leaching and is potentially a nutrient management option in sandy soils. Red mud has the potential to reduce the impact of agriculture on the estuarine environment and has implications for the continued expansion and intensification of agriculture in the Peel-Harvey catchment.     

A new test for cleaning efficiency assessment of cleaners for hard surfaces

A new test was developed to assess the efficiency of no-wiping hard-surface cleaning. The test allows cleaner comparisons according to their ability to remove greasy soils. The chosen approach minimizes the mechanical forces applied while cleaning so that the interactions between a detergent solution and the soil to be removed can be characterized. For this, immersion cleaning was chosen, with coated stainless steel as substrate and pigmented oils as the model soil. Several parameters were studied in defined ranges using the Experimental Design method and systematic comparisons. The test shows high reliability on degreasing assessments and is there-fore especially suited to optimization of nonionic surfactant mixes. The originality of the test lies in the possibility of keeping a visual trace of the cleaned substrate appearance by imprinting it on a piece of paper. The validation of the test leads to corroboration of several practical observations. Temperature and agitation play a major role in cleaning efficiency. Detergent solution concentration is a more relevant parameter than pH. Sodium carbonate is shown to have a higher buffering effect than pentahydrated sodium metasilicate. The test is easy to set up, highly sensitive, and can be adapted to solve the problems encountered by formulators of detergent cleaners, such as screening the best ethoxylated fatty alcohol mix for better degreasing properties.     

高吸水性树脂在农业中的应用

介绍了高吸水性树脂的吸水机理及农用高吸水性树脂的性能、种类和使用方法，分析了高吸水性树脂抗旱节水、改良土壤和促进作物生长的作用机理和影响因素，指出了当前研究中所存在的问题及改进的方向.     

二氧化钛固载杂多酸催化剂的制备及其光催化性能研究

采用浸渍法以TiO2为载体制备了固载型杂多酸光催化剂--H3PW12O40/TiO2,H8SiW12O42/TiO2,H7PMo12O42/TiO2.通过Hammett指示剂与紫外光谱相结合的方法测定固体杂多酸催化剂的酸度,分别考察杂多酸种类、浸渍时间、浸渍浓度、烧结方式、烧结温度对催化剂酸度的影响,并对所制备的催化剂进行了红外光谱和光催化活性测试.结果表明,杂多酸固载到TiO2的表面,得到了催化活性较TiO2更强的复合杂多酸光催化剂,其对酸性大红3R的降解率从纯TiO2的79%提高到91%.以磷钨酸水溶液浸渍TiO2,浸渍浓度为0.10 mol·L-1 ,浸渍时间为28 h,烘干温度为120℃,微波炉焙烧功率为650 W,烧结时间为40 min制得的催化剂活性最高.在HPA-TiO2光催化系统中,杂多酸显著加速电子从TiO2表面到O2分子的传递,改变了TiO2光催化反应历程,从而提高光催化效率.     

氧化铝生产赤泥附液吸收H_2S实验研究

对氧化铝生产附产赤泥吸收净化H2 S废气进行了实验研究 ,赤泥附液吸收H2 S具有吸收效率高、吸收容量大、易控制 ,操作简便等优点 ,在较少时间内对H2 S的吸收效率保持在 90 %以上。     

包裹法国红色料在陶瓷领域应用的探索

探索包裹法国红色料在建筑陶瓷工业釉料、坯体中应用的工艺技术条件，采用正交实验方法找出包裹法国红色料在陶瓷釉料、外墙砖、地砖中的最佳发色条件：在釉料中一价的钾、钠离子特别利于该色料的发色；二价离子钡较好、钙次之、镁最差；法国红色料在普通熔块中发色不理想，在特制的熔块中发色良好。     

悬浮液进样FAAS法测定土壤样品中微量锰

采用悬浮液进样火焰原子吸收光谱法(FAAS法)测定土壤样品中微量锰;并对样品的粒度、悬浮液的浓度、介质酸度、校正方法及抗干扰等进行了探讨.结果表明,本法简便、快速、准确可靠.     

安克锰锌在荔枝树上施用的残留代谢消解规律与安全性评价

安克锰锌是烯酰吗啉两个异构体和代森锰锌组成的多元混合制剂。试样经粉碎、溶剂浸泡提取、混合柱净化,用气相色谱测定烯酰吗啉和代森锰锌母体(CS2),液相色谱测定代谢物乙撑硫脲(ETU)。仪器最低检出量:烯酰吗啉为1.436×10-12g,代森锰锌母体1.326×10-10g,ETU2.5×10-10g,最低检出浓度依次为0.02、0.025、0.02mg/kg,方法回收率依次为86.4%～90.8%、89.2%～95.9%、89.10%～95.13%;标准偏差为0.53～4.34;变异系数为0.58%～4.62%。安克锰锌在果皮中的消解方程广西和广东分别为C=1.2719e-0.1975T和C=1.045e-0.1972T,半衰期(T/2)均为3.5d;土壤中分别为C=0.8734e-0.1187T和C=0.6171e-0.1146T,半衰期(T/2)=6d;最高剂量250倍、最多施3次,最短距收期7d,在果肉中均未检出,果皮和土壤中的残留仅分别为0.1385～0.1745mg/kg和0.3105～0.3415mg/kg,均低于欧共体规定代森锰锌MRL值0.5mg/kg。     

Bioremediation of polycyclic aromatic hydrocarbons: current knowledge and future directions

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that have accumulated in the natural environment mainly as a result of anthropogenic activities such as the combustion of fossil fuels. Interest has surrounded the occurrence and distribution of PAHs for many decades due to their potentially harmful effects to human health. This concern has prompted researchers to address ways to detoxify/remove these organic compounds from the natural environment. Bioremediation is one approach that has been used to remediate contaminated land and waters, and promotes the natural attenuation of the contaminants using the in situ microbial community of the site. This review discusses the variety of fungi and bacteria that are capable of these transformations, describes the major aerobic and anaerobic breakdown pathways, and highlights some of the bioremediation technologies that are currently available. Copyright © 2005 Society of Chemical Industry     

Use of15N for fertilizer N recovery and N mineralization studies in semi-arid Kenya

Maize and beans were grown on a ferralsol at Kiboko, Kenya, with up to 120 kg N ha^–1. Within the 10 kg N ha^–1 plots,¹⁵N labelled fertilizer was applied in microplots. There was no significant response in yield to fertilizer N and labelled N recovery was low, being 7.5% or less in one season and 17.7% or less in the second season. Samples of Kiboko soil at four different water contents were incubated and the rate of gross N mineralization over 7 days was calculated, utilizing¹⁵N labelling of the mineral N. Gross N mineralization increased greatly with soil moisture and a fitted relationship between gross N mineralization rate and soil water content was obtained. Using measurements of soil water content at the field site, daily values of the soil N supply by gross mineralization were calculated. On average, modelled gross soil N mineralized could supply much (> 69%) of the N removed from the plots. It is suggested that the lack of response to fertilizer N may be explained by the coincidence of a high rate of N mineralization, and increased crop demand, caused by the onset of rain.