Photodegradation of organic pollutants in water by immobilized porphyrins and phthalocyanines

2016 ◽  
Vol 20 (01n04) ◽  
pp. 150-166 ◽  
Author(s):  
Lucía Fernández ◽  
Valdemar I. Esteves ◽  
Ângela Cunha ◽  
Rudolf J. Schneider ◽  
João P.C. Tomé
Keyword(s):  
Water Treatment ◽  
Organic Pollutants ◽  
Photocatalytic Performance ◽  
Photocatalytic Properties ◽  
Photo Oxidation ◽  
New Methods ◽  
Different Types ◽  
Pollution Impact ◽  
Water Treatments

New methods for water treatment are required as a result from an increasing awareness in the reduction of the pollution impact in the environment. In the perspective of the photo-oxidation of organic pollutants present in water, the principal incentive for the preparation of heterogeneous photocatalysts is their easy recovery from the reaction mixture, which allows their reuse in successive runs, minimizing the loss of their original photocatalytic properties. Different types of supports can be used in the immobilization of photoactive species, such as porphyrins (Pors) and phthalocyanines (Pcs). This mini-review will consider the different methodologies for the immobilization of Pors and Pcs and their photocatalytic performance in the photodegradation of organic pollutants in water, addressing also their recycling ability in successive water treatments.

Advanced Oxidation Processes for Wastewater Remediation: Fundamental Concepts to Recent Advances

2021 ◽  
pp. 37-86
Keyword(s):  
Water Treatment ◽  
Organic Pollutants ◽  
Large Scale ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Oxidation Potential ◽  
Wastewater Remediation ◽  
Oxidation Processes ◽  
Sludge Disposal ◽  
Different Types

Industrialization and modernization in recent times have led to a water crisis across the world. Conventional methods of water treatment like physical, chemical and biological methods which comprise of many commonly used techniques like membrane separation, adsorption, chemical treatment etc. have been in use for many decades. However, problems like sludge disposal, high operating costs etc. have led to increased focus on Advanced Oxidation Processes (AOPs) as alternative treatment methods. AOPs basically involve reactions relying on the high oxidation potential of the hydroxyl (OH•) free radical. They have the potential to efficiently treat various toxic, organic pollutants and complete degradation of contaminants (mineralization) of emerging concern. Many different types of homogenous as well as heterogenous AOPs have been studied viz: UV/H2O2, Fenton, Photo-Fenton, Sonolysis, Photocatalysis etc. for treatment of a wide variety of organic pollutants. Different AOPs are suitable for different types of wastewater and hence proper selection of the right technique for a particular type of pollutant is required. The inherent advantages offered by AOPs like elimination of sludge disposal problems, operability under mild conditions, ability to harness sunlight, non selective nature (ability to degrade all organic and microbial contamination) etc. have made it one of the most actively researched areas in recent times for wastewater treatment. Despite the benefits and intense research, commercial applicability of AOPs as a practical technique for treating wastewater on a large scale is still far from satisfactory. Nevertheless, positive results in lab scale and pilot plant studies make them a promising water treatment technique for the future. In the present chapter, an attempt has been made to discuss all aspects of AOPs beginning with the fundamental concepts, classification, underlying mechanism, comparison, commercialization to the latest developments in AOPs.

Advanced Oxidation Processes for Wastewater Remediation: Fundamental Concepts to Recent Advances

2021 ◽  
pp. 37-86
Keyword(s):  
Water Treatment ◽  
Organic Pollutants ◽  
Large Scale ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
Oxidation Potential ◽  
Wastewater Remediation ◽  
Oxidation Processes ◽  
Sludge Disposal ◽  
Different Types

Industrialization and modernization in recent times have led to a water crisis across the world. Conventional methods of water treatment like physical, chemical and biological methods which comprise of many commonly used techniques like membrane separation, adsorption, chemical treatment etc. have been in use for many decades. However, problems like sludge disposal, high operating costs etc. have led to increased focus on Advanced Oxidation Processes (AOPs) as alternative treatment methods. AOPs basically involve reactions relying on the high oxidation potential of the hydroxyl (OH•) free radical. They have the potential to efficiently treat various toxic, organic pollutants and complete degradation of contaminants (mineralization) of emerging concern. Many different types of homogenous as well as heterogenous AOPs have been studied viz: UV/H2O2, Fenton, Photo-Fenton, Sonolysis, Photocatalysis etc. for treatment of a wide variety of organic pollutants. Different AOPs are suitable for different types of wastewater and hence proper selection of the right technique for a particular type of pollutant is required. The inherent advantages offered by AOPs like elimination of sludge disposal problems, operability under mild conditions, ability to harness sunlight, non selective nature (ability to degrade all organic and microbial contamination) etc. have made it one of the most actively researched areas in recent times for wastewater treatment. Despite the benefits and intense research, commercial applicability of AOPs as a practical technique for treating wastewater on a large scale is still far from satisfactory. Nevertheless, positive results in lab scale and pilot plant studies make them a promising water treatment technique for the future. In the present chapter, an attempt has been made to discuss all aspects of AOPs beginning with the fundamental concepts, classification, underlying mechanism, comparison, commercialization to the latest developments in AOPs.

scholarly journals Fabrication of Ag/AgBr/Ag3VO4 composites with high visible light photocatalytic performance

RSC Advances ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 5100-5109 ◽  
Author(s):  
Wenxue Li ◽  
Qianlin Chen ◽  
Xianyu Lei ◽  
Shang Gong
Keyword(s):  
Visible Light ◽  
Organic Pollutants ◽  
Photocatalytic Performance ◽  
Photocatalytic Properties ◽  
Precipitation Method ◽  
Continuous Precipitation ◽  
Visible Light Photocatalytic

Ag/AgBr/Ag3VO4 composites were synthesized by a simple continuous precipitation method, which were used to degrade organic pollutants and found to have excellent photocatalytic properties.

A treatability index for reservoir water

1998 ◽  
Vol 37 (2) ◽  
pp. 27-33 ◽  
Author(s):  
C. T. Ta ◽  
C. A. Woodward
Keyword(s):  
Water Treatment ◽  
Filtration Rate ◽  
Water Area ◽  
Reservoir Water ◽  
Algal Concentration ◽  
Run Lengths ◽  
Water Treatments

A Treatability Index is developed to allow comparison of different reservoir waters according to their effects on a water treatments works. For the water treatment works which employs rapid gravity filters, the index is the product of the algal concentration, the clarification coefficients of algae and the filtration rate. The index is applied to reservoir waters within Thames Water area. Algae observed in reservoirs are grouped according to their shapes. Among these groups, twenty frequently observed species were selected and their clarification coefficients were measured. The treatability index was then evaluated for different waters and at different times of the year. The results were correlated to the filter run lengths and the development of headloss across the filters.

scholarly journals Genetic loci regulating cadmium content in rice grains

Euphytica ◽  
2021 ◽  
Vol 217 (3) ◽  
Author(s):  
Gareth J. Norton ◽  
Anthony Travis ◽  
Panthita Ruang-areerate ◽  
Graeme W. Nicol ◽  
Ayotunde A. Adeosun ◽  
...  
Keyword(s):  
Water Treatment ◽  
Water Regime ◽  
Field Experiments ◽  
Cadmium Concentration ◽  
Chromosome 9 ◽  
Chromosome 7 ◽  
Cadmium Content ◽  
Rice Grains ◽  
Water Treatments ◽  
Grain Cadmium

AbstractIt has been estimated that up to 90% of human exposure to cadmium is through food, and that cadmium within rice grains can be a major contributor to that dietary source. In this study genome wide association mapping was conducted on the Bengal and Assam Aus Panel (BAAP) of rice to identify quantitative trait loci and candidate genes for lowering grain cadmium. Field experiments were conducted over two years under two different irrigation systems: continually flooded and alternate wetting and drying (AWD). There was significant effects of water treatment, genotype, and genotype by water treatment interaction. Importantly, AWD increased grain cadmium, on average, by 49.6% and 108.8% in year 1 and 2 respectively. There was between 4.6 and 28 fold variation in cadmium concentration. A total of 58 QTLs were detected but no loci are clearly specific to one water regime despite approximately 20% of variation attributable to genotype by water regime interaction. A number of QTLs were consistent across most water treatments and years. These included QTLs on chromosome 7 (7.23–7.61, 8.93–9.04, and 29.12–29.14 Mbp), chromosome 5 (8.66–8.72 Mbp), and chromosome 9 (11.46–11.64 Mbp). Further analysis of the loci on chromosome 7 (8.93–9.04 Mbp), identified the candidate gene OsNRAMP1, where cultivars with a deletion upstream of the gene had higher concentrations of cadmium compared to the cultivars that did not have the deletion. The distribution of alleles within the BAAP suggest this QTL is easily detected in this population because it is composed of aus cultivars. Local genome cluster analysis suggest high Cd alleles are uncommon, but should be avoided in breeding.

scholarly journals The Nanosystems Involved in Treating Lung Cancer

Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 682
Author(s):  
Andreea Crintea ◽  
Alina Gabriela Dutu ◽  
Gabriel Samasca ◽  
Ioan Alexandru Florian ◽  
Iulia Lupan ◽  
...  
Keyword(s):  
Lung Cancer ◽  
Side Effects ◽  
Chromosomal Rearrangements ◽  
Sirna Delivery ◽  
Delivery Systems ◽  
Inorganic Nanoparticles ◽  
New Methods ◽  
Different Types ◽  
Or Gene ◽  
The Many

Even though there are various types of cancer, this pathology as a whole is considered the principal cause of death worldwide. Lung cancer is known as a heterogeneous condition, and it is apparent that genome modification presents a significant role in the occurrence of this disorder. There are conventional procedures that can be utilized against diverse cancer types, such as chemotherapy or radiotherapy, but they are hampered by the numerous side effects. Owing to the many adverse events observed in these therapies, it is imperative to continuously develop new and improved strategies for managing individuals with cancer. Nanomedicine plays an important role in establishing new methods for detecting chromosomal rearrangements and mutations for targeted chemotherapeutics or the local delivery of drugs via different types of nano-particle carriers to the lungs or other organs or areas of interest. Because of the complex signaling pathways involved in developing different types of cancer, the need to discover new methods for prevention and detection is crucial in producing gene delivery materials that exhibit the desired roles. Scientists have confirmed that nanotechnology-based procedures are more effective than conventional chemotherapy or radiotherapy, with minor side effects. Several nanoparticles, nanomaterials, and nanosystems have been studied, including liposomes, dendrimers, polymers, micelles, inorganic nanoparticles, such as gold nanoparticles or carbon nanotubes, and even siRNA delivery systems. The cytotoxicity of such nanosystems is a debatable concern, and nanotechnology-based delivery systems must be improved to increase the bioavailability, biocompatibility, and safety profiles, since these nanosystems boast a remarkable potential in many biomedical applications, including anti-tumor activity or gene therapy. In this review, the nanosystems involved in treating lung cancer and its associated challenges are discussed.

scholarly journals Forces Necessary to Initiate Dispersal for Three Tumbleweeds

2008 ◽  
Vol 1 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Dirk V. Baker ◽  
K. George Beck ◽  
Bogusz J. Bienkiewicz ◽  
Louis B. Bjostad
Keyword(s):  
Water Treatment ◽  
Conversion Factor ◽  
Common Garden ◽  
High Water ◽  
Western United States ◽  
Field Collection ◽  
Stem Strength ◽  
Wind Velocities ◽  
Diffuse Knapweed ◽  
Water Treatments

AbstractAlthough diffuse knapweed, kochia, and Russian thistle are important tumbleweeds of the western United States, environmental factors contributing to their dispersal are not well understood. Bolting rosettes of these species were transplanted to pots and reared in a common garden to determine the affect of postsenescence water on stem strength. There were no differences in stem strength among three water treatments for Russian thistle. Kochia, under moderate water treatment, required more than twice the force to break compared to plants under the zero and high water treatments. In contrast, diffuse knapweed plants under zero water treatment required four to six times greater force to break compared to plants under the moderate and high water treatments. There was a strong difference in diffuse knapweed stem strength between field collection sites that corresponded to observed differences in proportion of plants tumbling. A wind tunnel was used to develop a conversion factor between force and wind velocity. Wind velocities necessary to break diffuse knapweed stems ranged from 16 to 37 m/s (36 to 77 mph).

Sign in / Sign up

Export Citation Format

Share Document