scholarly journals A Study on TiO2 Surface Texturing Effect for the Enhancement of Photocatalytic Reaction in a Total Phosphorous Concentration Measurement System

Micromachines ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1163
Author(s):  
Jae Keon Kim ◽  
Seung Deok Kim ◽  
Jae Yong Lee ◽  
Chang Hee Kim ◽  
Hyeon-Su Lee ◽  
...  
Keyword(s):  
Total Phosphorus ◽  
Aquatic Ecosystem ◽  
Surface Texturing ◽  
Algal Growth ◽  
High Water ◽  
Inorganic Materials ◽  
Water Supply Systems ◽  
Photocatalytic Reaction ◽  
Single Chip ◽  
Photocatalytic Materials

Powerful sunlight, a high water temperature, and stagnation in the water flow induce eutrophication in rivers and lakes, which destroys the aquatic ecosystem and threatens the downstream water supply systems. Accordingly, it is very important to perform real-time measurements of nutrients that induce algal growth, especially total phosphorus, to preserve and manage the aquatic ecosystem. To conduct quantitative analysis of the total phosphorus in the aquatic ecosystem, it is essential to perform a pretreatment process and quickly separate the phosphorus, combined with organic and inorganic materials, into a phosphate. In this study, the sandblasting process was used for the physical etching of the wafer, and photocatalytic materials were deposited on the surface with various roughness in order to improve the photocatalytic reaction surface and efficiency. The photocatalytic reaction was applied to combine the pretreated sample with the coloring agent for color development, and the absorbance of the colored sample was analyzed quantitatively to compare and evaluate the characteristics, followed by the surface increase in the photocatalytic materials. In addition, the pretreatment and measurement parts were materialized in a single chip to produce a small and light total phosphorus analysis sensor.

Lake Paranoá, Brasília, Brazil: Integrated Management Plan for its Restoration

1992 ◽  
Vol 27 (2) ◽  
pp. 271-286 ◽  
Author(s):  
Sonia Paulino Mattos ◽  
Irene Guimarães Altafin ◽  
Hélio José de Freitas ◽  
Cristine Gobbato Brandão Cavalcanti ◽  
Vera Regina Estuqui Alves
Keyword(s):  
Total Phosphorus ◽  
Drainage Basin ◽  
Integrated Management ◽  
Algal Growth ◽  
Nutrient Content ◽  
Management Plan ◽  
Cylindrospermopsis Raciborskii ◽  
Phosphorus Concentration ◽  
Limiting Factor ◽  
Total Phosphorus Concentration

Abstract Built in 1959, Lake Paranoá, in Brasilia, Brazil, has been undergoing an accelerated process of nutrient enrichment, due to inputs of inadequately treated raw sewage, generated by a population of 600,000 inhabitants. Consequently, it shows high nutrient content (40 µg/L of total phosphorus and 1800 µg/L of total nitrogen), low transparency (0.65 m) and high levels of chlorophyll a (65 µg/L), represented mainly by Cylindrospermopsis raciborskii and sporadic bloom of Microcystis aeruginosa, which is being combatted with copper sulphate. With the absence of seasonality and a vertical distribution which is not very evident, the horizontal pattern assumes great importance in this reservoir, in which five compartments stand out. Based on this segmentation and on the identification of the total phosphorus parameter as the limiting factor for algal growth, mathematical models were developed which demonstrate the need for advanced treatment of all the sewage produced in its drainage basin. With this, it is expected that a process of restoration will be initiated, with a decline in total phosphorus concentration to readings below 25 µg/L. Additional measures are proposed to accelerate this process.

Lab-on-a-chip based total-phosphorus analysis device utilizing a photocatalytic reaction

2018 ◽  
Vol 140 ◽  
pp. 100-108 ◽  
Author(s):  
Dong Geon Jung ◽  
Daewoong Jung ◽  
Seong Ho Kong
Keyword(s):  
Total Phosphorus ◽  
Lab On A Chip ◽  
Photocatalytic Reaction

Relationships among nutrients, algae, and land use in urbanized southern California streams

2006 ◽  
Vol 63 (12) ◽  
pp. 2621-2638 ◽  
Author(s):  
Lilian B Busse ◽  
Juliet C Simpson ◽  
Scott D Cooper
Keyword(s):  
Land Use ◽  
Total Phosphorus ◽  
Algal Biomass ◽  
Southern California ◽  
Stream Water ◽  
Algal Growth ◽  
Nutrient Concentrations ◽  
Total Chlorophyll ◽  
Impervious Surfaces ◽  
High Nutrient

We surveyed algal cover, algal biomass, and physical and chemical factors at 14 sites representing a range of land use types in the Malibu Creek watershed in southern California, USA. We also conducted nutrient diffuser substrate experiments to identify the nutrient limiting algal growth. Algal biomass increased with urbanization, reaching very high levels in the most urbanized streams (up to 322.4 mg chlorophyll a·m-2). Total nitrogen, total phosphorus, and benthic and total chlorophyll concentrations were positively correlated with the proportion of upstream land covered by impervious surfaces. Relationships between land use and algal biomass or nutrient concentrations were evaluated at 100 m, 500 m, and whole subwatershed scales. The closest relationships were found at the 500 m scale, where 56% of the variation in total chlorophyll could be explained by the proportion of land within a 500 m radius upstream covered by impervious surfaces. Floating macroalgae were observed in the summer in pools with high nutrient and light levels, whereas benthic algal biomass was positively related to total phosphorus concentrations and current speed. Other methods of determining nutrient limitation (nutrient diffuser substrate experiment, molar N/P ratios in stream water) produced conflicting results, possibly because algal growth was saturated by high nutrient levels at some of the study sites.

A Study of the Effects of Nitrogen and Phosphorus on Aquatic Ecosystem Health Status

2013 ◽  
Vol 448-453 ◽  
pp. 864-867
Author(s):  
Yi Xin Xu ◽  
Hua Yong Zhang ◽  
Xiang Xu ◽  
Jing Zhao ◽  
Fei Li
Keyword(s):  
Health Status ◽  
Total Nitrogen ◽  
Total Phosphorus ◽  
Aquatic Ecosystem ◽  
Ecosystem Health ◽  
Nitrogen And Phosphorus ◽  
Significant Change

Eco-exergy which is a thermodynamic indicator is applied to assess the ecosystem health status of QiXing Lake. And effects of nitrogen and phosphorus on ecosystem health status have been investigated. The results indicate that the ecosystem which contains macrophytes has the better health status than that does not contain macrophytes when they have the same concentration of nitrogen or phosphorus. The ecosystem health status decreased as the concentration of total nitrogen increased when the ecosystem contains macrophytes. However, the ecosystem health status has not significant change as the concentration of total nitrogen increased when the ecosystem does not contains macrophytes. It has the same law for total phosphorus.

Estuarine algal responses to increasing nitrate concentrations during closed mouth conditions of oligotrophic systems: a laboratory microcosm experiment

2018 ◽  
Vol 61 (6) ◽  
pp. 559-572 ◽  
Author(s):  
Daniel Alan Lemley ◽  
Monique Nunes ◽  
Janine Barbara Adams
Keyword(s):  
Community Dynamics ◽  
Temporal Dynamics ◽  
Inorganic Nitrogen ◽  
Algal Growth ◽  
Experimental Period ◽  
High Water ◽  
Algal Community ◽  
Microcosm Experiment ◽  
Nitrate Addition ◽  
Enriched Environments

AbstractThe increasing incidence of eutrophication has potentially detrimental socio-economic and ecological consequences. This study aimed to elucidate the temporal dynamics of algal communities in response to increasing initial concentrations of inorganic nitrogen (particularly nitrate) – central components of eutrophication. A contained microcosm experiment was designed to mimic the conditions of shallow oligotrophic estuaries with high water residence times. Phytoplankton, microphytobenthos and filamentous algal community dynamics were observed over a 28-day experimental period under different nitrate regimes. Key observations included (1) accelerated filamentous algal growth, (2) rapid loss of phytoplankton biomass and abundance, and (3) reduced benthic diatom species diversity and richness in the “1.0 μmNitrate Addition” treatment. Additionally, model results highlighted the positive relationship between filamentous algal growth and increased water temperature. From a global change perspective, the decline in microalgal abundance and diversity at the onset of filamentous algal growth in warm, N-enriched environments suggests a potential uncoupling of trophic pathways. However, the “Control” and “0.5 μmNitrate Addition” treatments were similar in their algal responses, highlighting the ability of ecosystems to absorb small disturbances. Thus, it is critical that estuarine resilience is preserved to ensure continued provision of invaluable ecosystem services.

Bioavailability of Phosphorus Fractions for Incepting of Chlorella pyrenoidosa in the Lower Reaches of the Hanjiang River in China

2011 ◽  
Vol 183-185 ◽  
pp. 3-7
Author(s):  
Jian Ru Tian ◽  
Guo Li Chen ◽  
Guang Feng Kang ◽  
Xiu Ping Zheng
Keyword(s):  
Total Phosphorus ◽  
Water Samples ◽  
Algal Growth ◽  
Chlorella Pyrenoidosa ◽  
P Fractions ◽  
Sediment Samples ◽  
Floodplain Sediment ◽  
Hanjiang River ◽  
Mn Oxides ◽  
Exchangeable P

Using total phosphorus (TP) concentrations to estimate eutrophication risk is problematic for management purposes, as only some forms of P are biologically available for phytoplankton growth. This study estimated the bioavailability of P fractions of water and the floodplain sediment in the lower reaches of the Hanjiang River in China using multiple regressions. And the effects of concentrations of P fractions on algal growth were also studied. The results showed that the total soluble P (TSP) and the particulate P (PP) can well predict the growth of Chlorella pyrenoidosa in water samples. And the exchangeable P (exch-P) and the P bound to Al, Fe, and Mn oxides and hydroxides (Fe/Al–P) were adapted to predicting the growth of Chlorella pyrenoidosa in the floodplain sediment samples.

scholarly journals A Brief Overview of TiO2 Photocatalyst for Organic Dye Remediation: Case Study of Reaction Mechanisms Involved in Ce-TiO2 Photocatalysts System

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Milind Pawar ◽  
S. Topcu Sendoğdular ◽  
Perena Gouma
Keyword(s):  
Reaction Mechanisms ◽  
Organic Dye ◽  
World Population ◽  
Photocatalytic Reaction ◽  
Tio2 Photocatalyst ◽  
Bandgap Engineering ◽  
Environmental Cleanup ◽  
Tio2 Photocatalysts ◽  
Photocatalytic Materials

The ever-increasing world population and the rapid growth of industrialization globally make necessary the development of clean technologies and affordable materials for remediating environmental pollution from petroleum-based hydrocarbons and dyes, among others. Advanced photocatalytic materials may provide an excellent solution for environmental cleanup without generating toxic byproducts as they allow for the complete oxidation of the pollutants and their conversion to benign species. In this review, the basic principle of photocatalyst operation and the importance of bandgap engineering are discussed. TiO2 has been the default photocatalyst although it has several shortcomings. Doping of TiO2 with Ce has been explored extensively in the literature as a way to enable visible-light-activated photocatalysis and enhanced efficiency. Recent advances in the synthesis of Ce-modified TiO2 photocatalytic materials along with photocatalytic reaction mechanisms are summarized.

scholarly journals Advanced treatment of salty eutrophication water using algal-bacterial granular sludge: With focus on nitrogen removal, phosphorus removal, and lipid accumulation

BioResources ◽  
2019 ◽  
Vol 14 (4) ◽  
pp. 9518-9530
Author(s):  
Fansheng Meng ◽  
Yu Liu ◽  
Ping Zhang ◽  
Dongfang Liu ◽  
Wenli Huang
Keyword(s):  
Total Phosphorus ◽  
Lipid Accumulation ◽  
Inorganic Nitrogen ◽  
Algal Growth ◽  
Granular Sludge ◽  
Treatment Method ◽  
Added Value ◽  
Nitrogen And Phosphorus ◽  
Salinity Water ◽  
Total Inorganic Nitrogen

A new algal-bacterial granular sludge treatment method was used to treat salty eutrophication water. The results indicated that the treatment removed more than 98% of the total inorganic nitrogen and the total phosphorus after a 15 d cultivation period using 2% salinity simulated eutrophication water. For the 4% salinity simulated water, the total phosphorus was not able to be removed and was even higher in the effluent; and the total inorganic nitrogen was only removed 17%. Thus, the algal-bacterial granules were efficient for removing nitrogen and phosphorus in 2% salinity eutrophication water but were not effective for 4% salinity water. High levels of filamentous algae proliferation growing on the surface of the granules was primarily responsible for the good performance in 2% salinity water. However, the lipid accumulation was greatly enhanced (reactor R2 at a 27.6% increase and reactor R4 at a 107% increase) for both granule types due to the algal growth. Thus, treatment of the salty eutrophication water can also greatly increase the added-value of the algal-bacterial granules.

The Electro-Osmotic Device for Extensive Soil Dehydration

2012 ◽  
Vol 170-173 ◽  
pp. 937-940
Author(s):  
Tai Bin Cao
Keyword(s):  
High Frequency ◽  
Flow Measurement ◽  
High Water ◽  
Power Source ◽  
Single Chip ◽  
Osmotic Effect ◽  
The Core ◽  
Switch Mode ◽  
Special Power ◽  
Source Electrode

In order to improve the electro-osmotic effect in high water ratio soil dehydration consolidation, this paper introduced an electro-osmotic installation system for extensive soil draining which were composed by special power source, electrode, vacuum pump and flow measurement device etc. Among those above, the development of special power source was the core of the system, which was mainly introduced in this paper with power electrical technology and single chip SCM technology and constitutive digital high frequency switch mode power source. The system supported a plenty of technological operations. It was available in worksite.

Sign in / Sign up

Export Citation Format

Share Document