Harmful algal blooms(HABs) can elicit several negative effects on aquatic environment(such as depleting the oxygen, blocking the sunlight, destroying the habitats of organisms) and life health(including poisoning/kill...Harmful algal blooms(HABs) can elicit several negative effects on aquatic environment(such as depleting the oxygen, blocking the sunlight, destroying the habitats of organisms) and life health(including poisoning/killing marine mammals, birds and human). Among the various control strategies for HABs(physical manipulation needs lots of manpower and expensive equipment, chemicals treatment has some toxic byproduct and high residual, microbial agents only has limited in laboratory research), the coagulation-flocculation of HAB species by modified clay(MC) has been proven to be an effective, lowcost and environmentally friendly method that has been widely applied in the field, particularly in eastern Asia. In order to examine the long-term effects of MC treatment, this study investigated the alternations in seawater of Skeletonema costatum, a high biomass dominant HAB species along the Chinese coast, by comparing the degradation of S. costatum detritus(A1) with the application of MC treatment(A2) and MC treatment in sediment condition(A3). The low dosage of 0.25 g/L MC could efficiently remove 4×108 cells/L of S. costatum cells within 3.5 h(approximately 97% removal). In addition, the results showed that both inorganic and organic nutrients were effectively reduced from seawater by MC particles. Compared to the total nitrogen(TN) and total phosphorus(TP) concentrations in A1 seawater, 44% of TN and 93% of TP in A2 seawater, as well as 72% of TN and 93% of TP in A3 seawater were removed during the onemonth incubation period. Simultaneously, 64% of DISi in A2 and 44% of DISi in A3 significantly decreased( P <0.001). This study demonstrated that MC treatment was able to significantly increase the downward flux of nutrients and delay the release velocity of inorganic nutrient from MC-algae matrix into the overlying seawater, particularly within sediment environment.展开更多
This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, nor...This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash （ranging from 6.49g to 12.73%）, a high content of volatile matter （33,32-37.45%） and high gross calorific values （7430-8880 kcal/kg）. The mineral matter of the coal samples studied is made up of dolomite （〉909g）, quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively cor- related with ash content suggesting an association with inorganic constituents. Based on statistical anal- yses, concentrations of trace elements such as Co （51.3 ×10^-6-152.9× 10^-6）, Ba （368× 10^-6-3297.4×10^-6）, Cr （65.5 ×10^-6-194.2 × 10^-6）, Mo （5.6 × 10^-6-18.2× 10^-6）, Hi （72.9 × 10^-6-152.9 × 10^-6） and V （245.5 × 10^-6-520 ×10^-6） are higher than world coal averages. However, low concentration of some vol- atile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.展开更多
This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and...This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and MAS-NMR analysis. Preliminary treatment was adopted to prepare the starting sample that is placed in contact with NaOH solution at variable concentration. A specific hydrothermal reactor, allowing the control ofpH 〉 9, temperature and a continuous stirring of the sample in the NaOH solution; was used to achieve these syntheses. The obtained results showed that, for concentration value ~IN, the final complex presented characteristic XRD and MAS-NMR line of zeolite P. For 3N solution concentration we obtained zeolite HS. All synthesize process are controlled by XRD and MAS-NMR investigation.展开更多
The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffrac...The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffractometer and atomic absorption spectrophotometer （AAS）, respectively. Performance efficiency studies were conducted to determine the best combination ratio of sand-clay/pebbles. Sand-clay fortified with pebbles in the ratio 3：1 gave the optimum water purification while combination ratio 1：3 gave the least. The fortified sand-clays were used in the treatment of wastewater from rural locality. On the other hand, bacteria play an important role in determining the properties and behavior of clay minerals in natural environments and such interactions have great potential for creating stable biofilms and carbon storage sites in soils, but our knowledge of these interactions are far from complete. The purpose of this study was to understand better the effects of bacteria-generated biofilms on clay interlayer expansion. Mixtures of a colloidal, 2-water smectite clay and Pseudomonas aereginosae in a minimal media suspension evolve into a polysaccharide-rich biofilm aggregate in time-series experiments lasting up to 1 week. X-ray diffraction analysis reveals that upon aggregation, the clay undergoes an initial interlayer contraction.展开更多
基金Supported by the National Natural Science Foundation of China(No.41276115)the National Basic Research Program of China(973 Program)(No.2010CB428706)the Fund for Creative Research Groups by NSFC(No.41121064)
文摘Harmful algal blooms(HABs) can elicit several negative effects on aquatic environment(such as depleting the oxygen, blocking the sunlight, destroying the habitats of organisms) and life health(including poisoning/killing marine mammals, birds and human). Among the various control strategies for HABs(physical manipulation needs lots of manpower and expensive equipment, chemicals treatment has some toxic byproduct and high residual, microbial agents only has limited in laboratory research), the coagulation-flocculation of HAB species by modified clay(MC) has been proven to be an effective, lowcost and environmentally friendly method that has been widely applied in the field, particularly in eastern Asia. In order to examine the long-term effects of MC treatment, this study investigated the alternations in seawater of Skeletonema costatum, a high biomass dominant HAB species along the Chinese coast, by comparing the degradation of S. costatum detritus(A1) with the application of MC treatment(A2) and MC treatment in sediment condition(A3). The low dosage of 0.25 g/L MC could efficiently remove 4×108 cells/L of S. costatum cells within 3.5 h(approximately 97% removal). In addition, the results showed that both inorganic and organic nutrients were effectively reduced from seawater by MC particles. Compared to the total nitrogen(TN) and total phosphorus(TP) concentrations in A1 seawater, 44% of TN and 93% of TP in A2 seawater, as well as 72% of TN and 93% of TP in A3 seawater were removed during the onemonth incubation period. Simultaneously, 64% of DISi in A2 and 44% of DISi in A3 significantly decreased( P <0.001). This study demonstrated that MC treatment was able to significantly increase the downward flux of nutrients and delay the release velocity of inorganic nutrient from MC-algae matrix into the overlying seawater, particularly within sediment environment.
基金supported by the Iranian Institute for Geological Surveys and Mineral Exploration
文摘This study focuses on the geochemistry of trace elements and parameters of coal quality of bituminous coal belonging to the upper Triassic-lower Jurassic era, collected from the Galandrud region in Central Alborz, northern Iran. Galandrud coal on an air-dried basis are characterized by broad variation in the amount of ash （ranging from 6.49g to 12.73%）, a high content of volatile matter （33,32-37.45%） and high gross calorific values （7430-8880 kcal/kg）. The mineral matter of the coal samples studied is made up of dolomite （〉909g）, quartz, sphalerite, galena, pyrite and clay minerals. Major elements are positively cor- related with ash content suggesting an association with inorganic constituents. Based on statistical anal- yses, concentrations of trace elements such as Co （51.3 ×10^-6-152.9× 10^-6）, Ba （368× 10^-6-3297.4×10^-6）, Cr （65.5 ×10^-6-194.2 × 10^-6）, Mo （5.6 × 10^-6-18.2× 10^-6）, Hi （72.9 × 10^-6-152.9 × 10^-6） and V （245.5 × 10^-6-520 ×10^-6） are higher than world coal averages. However, low concentration of some vol- atile elements such as As, Hg and U are present in low concentrations of the various types of coal studied.
文摘This work focuses the effect of alkali-NaOH solution on the nature of synthesized zeolite from 2：1 Tunisian clays. This study was achieved using correlation between results obtained from X-ray diffraction （XRD） and MAS-NMR analysis. Preliminary treatment was adopted to prepare the starting sample that is placed in contact with NaOH solution at variable concentration. A specific hydrothermal reactor, allowing the control ofpH 〉 9, temperature and a continuous stirring of the sample in the NaOH solution; was used to achieve these syntheses. The obtained results showed that, for concentration value ~IN, the final complex presented characteristic XRD and MAS-NMR line of zeolite P. For 3N solution concentration we obtained zeolite HS. All synthesize process are controlled by XRD and MAS-NMR investigation.
文摘The ability of some Tunisian sand-clays in rural wastewater treatment was investigated in this study. The sand-clays were characterized by studying the mineralogical and geochemical characteristics using X-ray diffractometer and atomic absorption spectrophotometer （AAS）, respectively. Performance efficiency studies were conducted to determine the best combination ratio of sand-clay/pebbles. Sand-clay fortified with pebbles in the ratio 3：1 gave the optimum water purification while combination ratio 1：3 gave the least. The fortified sand-clays were used in the treatment of wastewater from rural locality. On the other hand, bacteria play an important role in determining the properties and behavior of clay minerals in natural environments and such interactions have great potential for creating stable biofilms and carbon storage sites in soils, but our knowledge of these interactions are far from complete. The purpose of this study was to understand better the effects of bacteria-generated biofilms on clay interlayer expansion. Mixtures of a colloidal, 2-water smectite clay and Pseudomonas aereginosae in a minimal media suspension evolve into a polysaccharide-rich biofilm aggregate in time-series experiments lasting up to 1 week. X-ray diffraction analysis reveals that upon aggregation, the clay undergoes an initial interlayer contraction.
