Phosphate recovery with granular acid-activated neutralized red mud: Fixed-bed column performance and breakthrough curve modelling

Granular acid-activated neutralized red mud (AaN-RM) has been successfully prepared with good chemical stability and physical strength. However, its potential for industrial application remains unknown. Therefore, the performance of granular AaN-RM for phosphate recovery in a fixed-bed column was investigated. The results demonstrated that the phosphate adsorption performance of granular AaN-RM in a fixed-bed column was affected by various operational parameters, such as the bed depth, flow rate, initial solution pH and initial phosphate concentration. With the optimal empty-bed contact time (EBCT) of 24.27 min, the number of processed bed volumes and the phosphate adsorption capacity reached 496.95 and 84.80 mg/g, respectively. Then, the saturated fixed-bed column could be effectively regenerated with a 0.5 mol/L HCl solution. The desorption efficiency remained as high as 83.45% with a low weight loss of 3.57% in the fifth regeneration cycle. In addition, breakthrough curve modelling showed that a 5-9-1 feed-forward artificial neural network (ANN) could be effectively applied for the optimization of the fixed-bed adsorption system; the coefficient of determination (R²) and the root mean square error (RMSE) evaluated on the validation-testing data were 0.9987 and 0.0183, respectively. Therefore, granular AaN-RM fixed-bed adsorption exhibits promising potential for phosphate removal and recovery from polluted water.     

基于地形位置指数的赤水河流域植被时空变化研究

地形因子和植被覆盖是区域灾害评价的关键指标,也是山区型村镇建设生态安全评估的重要内容.为探析山区型村镇建设的生态约束条件,以赤水河流域为研究对象,基于1998—2018年SPOT_VGT NDVI数据,利用地形位置指数（Topographic Position Index,TPI）和坡度位置指数方法,研究了赤水河流域植被生长季NDVI时空变化及地形分异特征.结果表明:①赤水河流域内,1998—2018年植被生长季平均NDVI呈缓慢上升趋势,斜率为0.004 7;NDVI>0.60的集中连片区域主要分布在古蔺县北部、赤水市大部和习水县西北部,占赤水河流域总面积的8.42%;Sen's slope在0.009~0.015区间时,赤水河流域植被生长增强趋势最明显,主要集中分布在赤水河中上游、二道河以及下游的大同河干流地区.②TPI在-39.4~34.3区间的面积最多,为6 221.63 km2,占赤水河流域总面积的34.05%;将赤水河流域坡度类型划分为山脊、上坡、中坡、平坡、下坡、山谷6个坡度位置类型,其中,中坡面积（7 792.02 km2）最大,占流域总面积的42.64%,表明TPI数值较小且坡度大于5°的区域是赤水河流域地形主体.③赤水河流域植被在山脊的平均NDVI最高,为0.747,且山脊平均Sen's slope最高,为0.007 2;山谷平均NDVI最低,为0.709.研究显示,赤水河流域植被分布在118.5~486.9的TPI区间或分布在山脊处时整体生长较好,且生长增强趋势最明显.      

红壤丘陵区典型流域地表水水环境特征研究——以浏阳河流域为例

选取浏阳河流域为例,根据近十年河流断面监测数据,采用改进的综合污染指数法来评价水质污染程度,研究了该红壤丘陵区典型河流水质的时空变化特征,并结合土地利用和土壤特征等分析地表水质变化原因。结果表明,改进的综合污染指数法有较好的适用性;从时间特征上看,由于面源污染加剧,使得浏阳河近十年的水质污染呈增长趋势;从空间特征上看,浏阳河从上游到下游,河流污染呈增长趋势,上游水质较好,中游表现为重金属铅和汞的污染较大,而下游则是氨氮污染加剧。     

Application of the benthic index of biotic integrity to environmental monitoring in Chesapeake Bay

The Chesapeake Bay benthic index of biotic integrity (B-IBI) was developed to assess benthic community health and environmental quality in Chesapeake Bay. The B-IBI provides Chesapeake Bay monitoring programs with a uniform tool with which to characterize bay-wide benthic community condition and assess the health of the Bay. A probability-based design permits unbiased annual estimates of areal degradation within the Chesapeake Bay and its tributaries with quantifiable precision. However, of greatest interest to managers is the identification of problem areas most in need of restoration. Here we apply the B-IBI to benthic data collected in the Bay since 1994 to assess benthic community degradation by Chesapeake Bay Program segment and water depth. We used a new B-IBI classification system that improves the reliability of the estimates of degradation. Estimates were produced for 67 Chesapeake Bay Program segments. Greatest degradation was found in areas that are known to experience hypoxia or show toxic contamination, such as the mesohaline portion of the Potomac River, the Patapsco River, and the Maryland mainstem. Logistic regression models revealed increased probability of degraded benthos with depth for the lower Potomac River, Patapsco River, Nanticoke River, lower York River, and the Maryland mainstem. Our assessment of degradation by segment and water depth provided greater resolution of relative condition than previously available, and helped define the extent of degradation in Chesapeake Bay.     

关于对"碱性高锰酸钾指数标准分析方法的错误"的讨论

《中国环境监测》于2006年8月第22卷第4期发表了一篇名为“碱性高锰酸钾指数标准分析方法的错误”的文章,该文作者通过配制不同浓度的葡萄糖标准溶液,分别用酸性法与碱性法来测定其高锰酸盐指数值,对相应的结果与计算公式进行讨论,指出碱性高锰酸钾操作方法与计算公式均存在错误,并提出了碱性高锰酸钾测定的修正方法与公式。文章对上述观点和结论有不同的看法,从碱性高锰酸钾指数标准分析方法的试验操作步骤及方法原理的理解入手,进行相关的阐述和讨论。     

用灰色关联度方法进行水污染因子分析

介绍了灰色关联度因子分析方法,以及此法在水污染因子分析中的应用.对于一般监测资料系列短而监测项目却较齐全的情况,应用本法是较适宜的.     

战略环境评价的工作程序

介绍了战略环境评价（法规、政策、计划和规划层次）工作程序的三个环节：评价方案的制定、评价实施和评价总结。并提出了战略环境评价指标体系制定的原则、战略环境评价的具体步骤及战略环境评价报告书的基本内容。     

区域水环境生物学评价浅析

本文论述了辽河三角洲区域地面水系浮游植物的种类分布，根据调查获得的生态学资料，探讨了其群落结构特征及其与水体环境质量的关系，运用“Ｓｈａｎｎｏｎ—Ｗｅａｖｅｒ多样性指数法”对区域水体质量进行了分类评价，并研究了浮游植物的多样性指数与水质理化污染指标之间的关系．     

战略环境评价及其应用初探

概述了战略环境价的概念、产生原因、研究现状及其工作程序，结合川南矿肥工程项目对它进行了应用初探，提出了计划、规划层次ＳＥＡ的方法和指标，并对我国环评工作提出了建议。     

活性艳红X-3B微波辅助光催化脱色的研究

研究了微波辅助光催化氧化(MW/UV/TiO2)处理活性艳红(X 3B)模拟废水。结果表明:400mg/LX 3B在反应150min时的脱色率由UV/TiO2体系的7.07%、MW体系的13.52%提高到了MW/UV/TiO2体系的56.35%。脱色反应速率随初始浓度(CX 3B)的增大而减慢;在强酸性介质中,脱色率更高;光照度(E)越强,越有利于X 3B脱色反应;改变催化剂投加量对X 3B脱色影响不大;H2O2浓度增加,X 3B脱色率升高;在以上条件下,X 3B的脱色反应均符合一级反应动力学方程,脱色反应中同时存在自由基反应与直接光解反应。