scholarly journals Conversion of Plastic Waste into Supports for Nanostructured Heterogeneous Catalysts: Application in Environmental Remediation

Surfaces ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 35-66
Author(s):  
Geovânia Cordeiro de Assis ◽  
Roberta Anjos de Jesus ◽  
Wélida Tamires Alves da Silva ◽  
Luiz Fernando Romanholo Ferreira ◽  
Renan Tavares Figueiredo ◽  
...  
Keyword(s):  
Environmental Remediation ◽  
Heterogeneous Catalysts ◽  
Environmental Concern ◽  
Low Cost ◽  
Metal Oxide Nanoparticles ◽  
Plastic Waste ◽  
Degree Of Crystallinity ◽  
Economic Losses ◽  
Commercial Polymers ◽  
Polymeric Supports

Plastics are ubiquitous in our society and are used in many industries, such as packaging, electronics, the automotive industry, and medical and health sectors, and plastic waste is among the types of waste of higher environmental concern. The increase in the amount of plastic waste produced daily has increased environmental problems, such as pollution by micro-plastics, contamination of the food chain, biodiversity degradation and economic losses. The selective and efficient conversion of plastic waste for applications in environmental remediation, such as by obtaining composites, is a strategy of the scientific community for the recovery of plastic waste. The development of polymeric supports for efficient, sustainable, and low-cost heterogeneous catalysts for the treatment of organic/inorganic contaminants is highly desirable yet still a great challenge; this will be the main focus of this work. Common commercial polymers, like polystyrene, polypropylene, polyethylene therephthalate, polyethylene and polyvinyl chloride, are addressed herein, as are their main physicochemical properties, such as molecular mass, degree of crystallinity and others. Additionally, we discuss the environmental and health risks of plastic debris and the main recycling technologies as well as their issues and environmental impact. The use of nanomaterials raises concerns about toxicity and reinforces the need to apply supports; this means that the recycling of plastics in this way may tackle two issues. Finally, we dissert about the advances in turning plastic waste into support for nanocatalysts for environmental remediation, mainly metal and metal oxide nanoparticles.

scholarly journals Fabrication of Rh-doped TiO2 nanofibers for Visible Light Degradation of Rhodamine B

2011 ◽  
Vol 1352 ◽  
Author(s):  
Emilly A. Obuya ◽  
William Harrigan ◽  
Tim O’Brien ◽  
Dickson Andala ◽  
Eliud Mushibe ◽  
...  
Keyword(s):  
Visible Light ◽  
Rhodamine B ◽  
Environmental Remediation ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Organic Pollutant ◽  
Heterogeneous Photocatalysis ◽  
Tio2 Nanofibers ◽  
Visible Light Degradation ◽  
Surface Modified

ABSTRACTThe synthesis and application of environmentally benign, efficient and low cost heterogeneous catalysts is increasingly important for affordable and clean chemical technologies. Nanomaterials have been proposed to have new and exciting properties relative to their bulk counterparts due to the quantum level interactions that exist at nanoscale. These materials also offer enormous surface to volume ratios that would be invaluable in heterogeneous catalysis. Recent studies point at titanium dioxide nanomaterials as having strong potential to be applied in heterogeneous photocatalysis for environmental remediation and pollution control. This work reports the use of surface modified anatase TiO2 nanofibers with rhodium (Rh) nanoparticles in the photodegradation of rhodamine B (RH-B), an organic pollutant. The dimensions of TiO2 nanofibers were 150±50 nm in diameter and the size of the Rh nanoparticles was ~5 nm. The Rh-doped TiO2 catalyst exhibited an enhanced photocatalytic activity in photodegradation of rhodamine B under visible light irradiation, with 95 % degradation within 180 minutes reaction time. Undoped TiO2 did not show any notable phocatalytic activity under visible light.

Carbon Nanocomposites: The Potential Heterogeneous Catalysts for Organic Transformations

2020 ◽  
Vol 24 ◽  
Author(s):  
Ambika ◽  
Pradeep Pratap Singh
Keyword(s):  
Heterogeneous Catalysis ◽  
Environmental Remediation ◽  
High Stability ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Chemical Properties ◽  
Organic Transformations ◽  
Wide Availability ◽  
Physical And Chemical ◽  
Carbon Based

: One of the major challenges in chemistry confronted by the chemists is the replacement of conventional homogeneous catalysts by heterogeneous catalysts for the development of green, sustainable and economical chemical processes. Recently, carbon based nanocomposites have attracted the attention of scientists due to their unique physical and chemical properties such as large surface area and pore volume, chemical inertness, high stability and high electrical conductivity. These NCs have been employed in energy storage, electronic devices, sensors, environmental remediation etc. Owing to the wide availability and low cost, carbon‐based‐materials have been utilized as supports for transition metals and other materials. The carbon based NCs offers a number of advantages such as high stability, easy recovery, reusability with often minimal leaching of metal ions, and green and sustainable approaches to heterogeneous catalysis for various organic transformations. Hence, they can be used as the substitute of the existing catalyst used for heterogeneous catalysis in industries. In this review, various processing methods for carbon based nanocomposites and their applications as heterogeneous catalyst for organic transformations like hydrogenation, oxidation, coupling, and multi‐component reactions, have been discussed.

Microplastic contamination in a conventional wastewater treatment plant in Thailand

2021 ◽  
pp. 0734242X2098205
Author(s):  
Katekanya Tadsuwan ◽  
Sandhya Babel
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Environmental Concern ◽  
Liquid Fraction ◽  
Treatment Plant ◽  
Dry Weight ◽  
Plastic Waste ◽  
Sludge Sample ◽  
Global Environmental ◽  
Urban Wastewater Treatment

Plastic waste has become a global environmental concern. One type of plastic waste is microplastics (MPs), which can spread easily in the environment. Wastewater effluent is one of the land-based sources of MPs. This study investigates the amount of microplastic (MP) pollution in an urban wastewater treatment plant (WWTP) in Thailand. Water samples were collected and examined to find the types, morphology and sources of MPs. Wastewater was filtered through a set of sieves ranging from 5 mm to 0.05 mm. Sludge samples were also collected to find the potential risk from the application of dried sewage sludge. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the types of MPs. The amount of MPs in the influent was 26.6 ± 11.8 MPs/L. More than one-third of MP particles were removed after a grit trap, followed by 14.24% removal in the secondary treatment. If the peak flow rate of the WWTP is reached, 2.32 × 109 MP particles can be released daily. The amount of MPs in a sludge sample was 8.12 ± 0.28 × 103 particles/kg dry weight. Dry sludge is one of the potential sources of MP contamination in agricultural soil. Most MPs in the liquid fraction and sludge sample were fibres. Results from FTIR analysis showed that the major types of MPs in the WWTP were polyester fibres, followed by polypropylene, polyethylene, silicone polymer and polystyrene. This finding indicates that a conventional WWTP may act as a path by which MPs enter the environment.

scholarly journals Innovative passive reinforcements for the gradual stabilization of a landslide according with the observational method

Landslides ◽  
2021 ◽  
Author(s):  
Lorenzo Brezzi ◽  
Alberto Bisson ◽  
Davide Pasa ◽  
Simonetta Cola
Keyword(s):  
Monitoring System ◽  
Low Cost ◽  
Economic Losses ◽  
Fe Model ◽  
Site Conditions ◽  
Observational Method ◽  
Rainy Period ◽  
Sustainable Solutions ◽  
Before And After ◽  
Set Up

AbstractA large number of landslides occur in North-Eastern Italy during every rainy period due to the particular hydrogeological conditions of this area. Even if there are no casualties, the economic losses are often significant, and municipalities frequently do not have sufficient financial resources to repair the damage and stabilize all the unstable slopes. In this regard, the research for more economically sustainable solutions is a crucial challenge. Floating composite anchors are an innovative and low-cost technique set up for slope stabilization: it consists in the use of passive sub-horizontal reinforcements, obtained by coupling a traditional self-drilling bar with some tendons cemented inside it. This work concerns the application of this technique according to the observational method described within the Italian and European technical codes and mainly recommended for the design of geotechnical works, especially when performed in highly uncertain site conditions. The observational method prescribes designing an intervention and, at the same time, using a monitoring system in order to correct and adapt the project during realization of the works on the basis of new data acquired while on site. The case study is the landslide of Cischele, a medium landslide which occurred in 2010 after an exceptional heavy rainy period. In 2015, some floating composite anchors were installed to slow down the movement, even if, due to a limited budget, they were not enough to ensure the complete stabilization of the slope. Thanks to a monitoring system installed in the meantime, it is now possible to have a comparison between the site conditions before and after the intervention. This allows the evaluation of benefits achieved with the reinforcements and, at the same time, the assessment of additional improvements. Two stabilization scenarios are studied through an FE model: the first includes the stabilization system built in 2015, while the second evaluates a new solution proposed to further increase the slope stability.

scholarly journals An Overview of Biodiesel Production via Calcium Oxide Based Catalysts: Current State and Perspective

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3950
Author(s):  
Hoora Mazaheri ◽  
Hwai Chyuan Ong ◽  
Zeynab Amini ◽  
Haji Hassan Masjuki ◽  
M. Mofijur ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Calcium Oxide ◽  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Biodiesel Production ◽  
Catalyst Synthesis ◽  
Process Improvements ◽  
Current State ◽  
The Common ◽  
Activity Mechanism

Biodiesel is a clean, renewable, liquid fuel that can be used in existing diesel engines without modification as pure or blend. Transesterification (the primary process for biodiesel generation) via heterogeneous catalysis using low-cost waste feedstocks for catalyst synthesis improves the economics of biodiesel production. Heterogeneous catalysts are preferred for the industrial generation of biodiesel due to their robustness and low costs due to the easy separation and relatively higher reusability. Calcium oxides found in abundance in nature, e.g., in seashells and eggshells, are promising candidates for the synthesis of heterogeneous catalysts. However, process improvements are required to design productive calcium oxide-based catalysts at an industrial scale. The current work presents an overview of the biodiesel production advancements using calcium oxide-based catalysts (e.g., pure, supported, and mixed with metal oxides). The review discusses different factors involved in the synthesis of calcium oxide-based catalysts, and the effect of reaction parameters on the biodiesel yield of calcium oxide-based catalysis are studied. Further, the common reactor designs used for the heterogeneous catalysis using calcium oxide-based catalysts are explained. Moreover, the catalytic activity mechanism, challenges and prospects of the application of calcium oxide-based catalysts in biodiesel generation are discussed. The study of calcium oxide-based catalyst should continue to be evaluated for the potential of their application in the commercial sector as they remain the pivotal goal of these studies.

scholarly journals A Microcosm Treatability Study for Evaluating Wood Mulch-Based Amendments as Electron Donors for Trichloroethene (TCE) Reductive Dechlorination

Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1949
Author(s):  
Edoardo Masut ◽  
Alessandro Battaglia ◽  
Luca Ferioli ◽  
Anna Legnani ◽  
Carolina Cruz Viggi ◽  
...  
Keyword(s):  
Electron Donor ◽  
Environmental Sustainability ◽  
Reductive Dechlorination ◽  
Environmental Remediation ◽  
Low Cost ◽  
Chlorinated Solvents ◽  
Electron Donors ◽  
Chlorinated Ethenes ◽  
Dehalococcoides Mccartyi ◽  
Wood Mulch

In this study, wood mulch-based amendments were tested in a bench-scale microcosm experiment in order to assess the treatability of saturated soils and groundwater from an industrial site contaminated by chlorinated ethenes. Wood mulch was tested alone as the only electron donor in order to assess its potential for stimulating the biological reductive dechlorination. It was also tested in combination with millimetric iron filings in order to assess the ability of the additive to accelerate/improve the bioremediation process. The efficacy of the selected amendments was compared with that of unamended control microcosms. The results demonstrated that wood mulch is an effective natural and low-cost electron donor to stimulate the complete reductive dechlorination of chlorinated solvents to ethene. Being a side-product of the wood industry, mulch can be used in environmental remediation, an approach which perfectly fits the principles of circular economy and addresses the compelling needs of a sustainable and low environmental impact remediation. The efficacy of mulch was further improved by the co-presence of iron filings, which accelerated the conversion of vinyl chloride into the ethene by increasing the H2 availability rather than by catalyzing the direct abiotic dechlorination of contaminants. Chemical analyses were corroborated by biomolecular assays, which confirmed the stimulatory effect of the selected amendments on the abundance of Dehalococcoides mccartyi and related reductive dehalogenase genes. Overall, this paper further highlights the application potential and environmental sustainability of wood mulch-based amendments as low-cost electron donors for the biological treatment of chlorinated ethenes.

scholarly journals Preparation of Organic Crystal Seed and Its Application in Improving the Functional Period of Biodegradable Agricultural Film

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 826
Author(s):  
Runmeng Qiao ◽  
Xin Wang ◽  
Guangjiong Qin ◽  
Qi Liu ◽  
Jialei Liu ◽  
...  
Keyword(s):  
Degradation Rate ◽  
Low Cost ◽  
Water Vapor Permeability ◽  
Growth Period ◽  
Nucleating Agent ◽  
Degree Of Crystallinity ◽  
Vapor Permeability ◽  
Agricultural Films ◽  
Degradation Degree ◽  
Water Holding

White pollution caused by agricultural films has recently attracted great attention. In some areas, the content of micro plastic in the soil has reached 30 kg/ha. The most effective way to solve this problem is to replace traditional polyethylene agricultural films with degradable agricultural films. The consistency between the degradation rate and the crop growth period has become the biggest obstacle for the wide application of such novel agricultural films. In this paper, crystallinity regulation is used to adjust the functional period of degradable agricultural films. In addition, an organic nucleating agent of polyethylenimine (PEI) is selected by doping it to poly(butylene adipate-co-terephthalate) (PBAT) polymers using a double-screw extruder. The PBAT doped with 1 wt% PEI films revealed a significant increase in mechanical properties, water holding capacity, and crystallinity compared with the pure PBAT film. There was a 31.9% increase in tensile strength, a 30.5% increase in elongation at break, a 29.6% increase in tear resistance, a 30.9% decrease in water vapor permeability, and a 3.1% increase in crystallinity. Furthermore, the induction period of PBAT doped with 1 wt% PEI under photoaging (without soil) was about 160 h longer than PBAT film, and the experienced biodegradation in soil (without light) was 1 week longer than PBAT film. Experimental results exhibited that the change of degradation degree was linearly proportional to the degree of crystallinity. This study proposes a convenient, low-cost, and effective method to adjust the crystallinity and change the degradation rate.

scholarly journals Screening of low-cost materials as heterogeneous catalysts for olive mill wastewater Fenton’s peroxidation

2020 ◽  
Vol 6 ◽  
pp. 161-167
Author(s):  
E. Domingues ◽  
F. Rodrigues ◽  
J. Gomes ◽  
M.J. Quina ◽  
S. Castro-Silva ◽  
...  
Keyword(s):  
Heterogeneous Catalysts ◽  
Low Cost ◽  
Olive Mill Wastewater ◽  
Olive Mill

Printing ultrathin graphene oxide nanofiltration membranes for water purification

2017 ◽  
Vol 5 (39) ◽  
pp. 20860-20866 ◽  
Author(s):  
Mahdi Fathizadeh ◽  
Huynh Ngoc Tien ◽  
Konstantin Khivantsev ◽  
Jung-Tsai Chen ◽  
Miao Yu
Keyword(s):  
Graphene Oxide ◽  
Water Purification ◽  
Inkjet Printing ◽  
Low Cost ◽  
Nanofiltration Membranes ◽  
Highly Effective ◽  
First Time ◽  
Polymeric Supports ◽  
Effective Water

We demonstrated for the first time that inkjet printing can be a low-cost, easy, fast, and scalable method for depositing ultrathin (7.5–60 nm) uniform graphene oxide (GO) nanofiltration membranes on polymeric supports for highly effective water purification.

scholarly journals A review on bioflocculation using microalgae for nutrient removal from waste water.

2021 ◽  
Vol 10 (1) ◽  
pp. 1-10
Author(s):  
Swathy Krishna
Keyword(s):  
Waste Water ◽  
Water Treatment ◽  
Surface Water ◽  
Nutrient Removal ◽  
Environmental Concern ◽  
Low Cost ◽  
Waste Water Treatment ◽  
Dual Purpose ◽  
Excellent Candidate ◽  
Conventional Methods

In recent decades, the eutrophication of surface water has become a major environmental concern. Increased concentration of nutrients such as nitrogen and phosphorous lead to eutrophication condition which highlights the demand for effective and economical methods of removing nitrogen and phosphorous from waste water. Bio flocculation using microalgae is an excellent candidate for satisfying the dual purpose of nutrient removal and waste water treatment. It has so many advantages over conventional methods such as toxic free, no chemical is needed, low cost etc. In this review the bio flocculation of microalgae, its mechanisms, applications and harvesting methods are discussed. Keywords: Bio flocculation, microalgae, nutrient removal, waste water treatment  

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