Preparation of highly open-porous functionalized PolyHIPE monoliths via emulsion templating for catalyst surface immobilization and thiophene chemical oxidation

2021 ◽  
Author(s):  
Safoora Sajad ◽  
Mohammad Reza Moghbeli
Keyword(s):  
Catalyst Surface ◽  
Chemical Oxidation ◽  
Surface Immobilization ◽  
Emulsion Templating

Bioadsorption of Multiple Heavy Metal Ions by Rhizophora Apiculate sp. and Elaesis Guineensis sp.

2017 ◽  
Vol 14 (1) ◽  
pp. 15
Author(s):  
M.B. Nicodemus Ujih ◽  
Mohammad Isa Mohamadin ◽  
Milla-Armila Asli ◽  
Bebe Norlita Mohammed
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Removal Efficiency ◽  
Heavy Metal Ions ◽  
Agricultural Waste ◽  
Living Organism ◽  
Heavy Metal Concentration ◽  
Industrial Area ◽  
Electrochemical Treatment ◽  
Chemical Oxidation

Heavy metal ions contamination has become more serious which is caused by the releasing of toxic water from industrial area and landfill that are very harmful to all living organism especially human and can even cause death if contaminated in small amount of heavy metal concentration. Currently, peoples are using classic method namely electrochemical treatment, chemical oxidation/reduction, chemical precipitation and reverse osmosis to eliminate the metal ions from toxic water. Unfortunately, these methods are costly and not environmentally friendly as compared to bioadsorption method, where agricultural waste is used as biosorbent to remove heavy metals. Two types of agricultural waste used in this research namely oil palm mesocarp fiber (Elaesis guineensis sp.) (OPMF) and mangrove bark (Rhizophora apiculate sp.) (MB) biomass. Through chemical treatment, the removal efficiency was found to improve. The removal efficiency is examined based on four specification namely dosage, of biosorbent to adsorb four types of metals ion explicitly nickel, lead, copper, and chromium. The research has found that the removal efficiency of MB was lower than OPMF; whereas, the multiple metals ions removal efficiency decreased in the order of Pb2+ > Cu2+ > Ni2+ > Cr2+.

Effects of Wet Chemical Oxidation on Surface Functionalization and Morphology of Highly Oriented Pyrolytic Graphite

2020 ◽  
Author(s):  
Mikhail Trought ◽  
Isobel Wentworth ◽  
Timothy Leftwich ◽  
Kathryn Perrine
Keyword(s):  
Surface Functionalization ◽  
Functional Group ◽  
Pyrolytic Graphite ◽  
Surface Oxidation ◽  
Chemical Oxidation ◽  
Synthesis Methods ◽  
Acid Solutions ◽  
Highly Oriented Pyrolytic Graphite ◽  
Wet Chemical ◽  
Surface Morphologies

The knowledge of chemical functionalization for area selective deposition (ASD) is crucial for designing the next generation heterogeneous catalysis. Surface functionalization by oxidation was studied on the surface of highly oriented pyrolytic graphite (HOPG). The HOPG surface was exposed to with various concentrations of two different acids (HCl and HNO3). We show that exposure of the HOPG surface to the acid solutions produce primarily the same -OH functional group and also significant differences the surface topography. Mechanisms are suggested to explain these strikingly different surface morphologies after surface oxidation. This knowledge can be used to for ASD synthesis methods for future graphene-based technologies.

A Solvent Free Synthetic Route for Cerium(IV) Metal-Organic Frame-works with UiO-66 Architecture and Their Photocatalytic Application

2019 ◽  
Author(s):  
Matteo Campanelli ◽  
Tiziana Del Giacco ◽  
Filippo De Angelis ◽  
Edoardo Mosconi ◽  
Marco Taddei ◽  
...  
Keyword(s):  
Density Functional ◽  
Chemical Oxidation ◽  
Solvent Free ◽  
Cerium Ammonium Nitrate ◽  
Benzylic Alcohols ◽  
Near Ultraviolet ◽  
Photocatalytic Application ◽  
Activity Density ◽  
Ultraviolet Light Irradiation ◽  
Metal Organic

<div> <p>A novel solvent-free synthesis for Ce-UiO-66 metal-organic frameworks (MOFs) is presented. The MOFs are obtained by simply grinding the reagents, cerium ammonium nitrate (CAN) and the carboxylic linkers, in a mortar for few minutes with the addition of a small amount of acetic acid (AcOH) as modulator (1.75 eq, o.1 ml). The slurry is then transferred into a 1 ml vial and heated at 120°C for 1 day. The MOFs have been characterized for their composition, crystallinity and porosity and employed as heterogenous catalysts for the photo-oxidation reaction of substituted benzylic alcohols to benzaldaldehydes under near ultraviolet light irradiation. The catalytic performances, such as yield, conversion and kinetics, exceed those of similar systems studied by chemical oxidation and using Ce-MOF as catalyst. Moreover, the MOFs were found to be reusable up to three cycles without loss of activity. Density functional theory (DFT) calculations gave an estimation of the band-gap shift due to the different nature of the linkers used and provide useful information on the catalytic activity experimentally observed.</p> </div>

Modeling the Electrical Double Layer to Understand the Reaction Environment in a CO2 Electrocatalytic System

2019 ◽  
Author(s):  
Divya Bohra ◽  
Jehanzeb Chaudhry ◽  
Thomas Burdyny ◽  
Evgeny Pidko ◽  
wilson smith
Keyword(s):  
Electric Field ◽  
Double Layer ◽  
Electrical Double Layer ◽  
Surface Reaction ◽  
Catalyst Surface ◽  
Local Reaction ◽  
Reaction Diffusion ◽  
Alkali Metal Cations ◽  
Applied Potential ◽  
Critical Aspect

<p>The environment of a CO<sub>2</sub> electroreduction (CO<sub>2</sub>ER) catalyst is intimately coupled with the surface reaction energetics and is therefore a critical aspect of the overall system performance. The immediate reaction environment of the electrocatalyst constitutes the electrical double layer (EDL) which extends a few nanometers into the electrolyte and screens the surface charge density. In this study, we resolve the species concentrations and potential profiles in the EDL of a CO<sub>2</sub>ER system by self-consistently solving the migration, diffusion and reaction phenomena using the generalized modified Poisson-Nernst-Planck (GMPNP) equations which include the effect of volume exclusion due to the solvated size of solution species. We demonstrate that the concentration of solvated cations builds at the outer Helmholtz plane (OHP) with increasing applied potential until the steric limit is reached. The formation of the EDL is expected to have important consequences for the transport of the CO<sub>2</sub> molecule to the catalyst surface. The electric field in the EDL diminishes the pH in the first 5 nm from the OHP, with an accumulation of protons and a concomitant depletion of hydroxide ions. This is a considerable departure from the results obtained using reaction-diffusion models where migration is ignored. Finally, we use the GMPNP model to compare the nature of the EDL for different alkali metal cations to show the effect of solvated size and polarization of water on the resultant electric field. Our results establish the significance of the EDL and electrostatic forces in defining the local reaction environment of CO<sub>2</sub> electrocatalysts.</p>

CHEMICAL OXIDATION OF TREATED TEXTILE EFFLUENT BY HYDROGEN PEROXIDE AND FENTON PROCESS

2010 ◽  
Vol 9 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Abdelnaser Omran ◽  
Hamidi Abdul Aziz ◽  
Marniyanti Mamat Noor
Keyword(s):  
Hydrogen Peroxide ◽  
Chemical Oxidation ◽  
Textile Effluent ◽  
Fenton Process

An efficient biotreatment process for polyvinyl alcohol containing textile wastewater

2013 ◽  
Vol 8 (3-4) ◽  
pp. 469-478 ◽  
Author(s):  
Sandip S. Magdum ◽  
Gauri P. Minde ◽  
Upendra S. Adhyapak ◽  
V. Kalyanraman
Keyword(s):  
Polyvinyl Alcohol ◽  
Process Optimization ◽  
Textile Wastewater ◽  
Cost Effective ◽  
Chemical Oxidation ◽  
High Rate ◽  
Microbial Consortia ◽  
Environment Friendly ◽  
Candida Sp ◽  
Textile Wastewater Treatment

The aim of this work was to optimize the biodegradation of polyvinyl alcohol (PVA) containing actual textile wastewater for a sustainable treatment solution. The isolated microbial consortia of effective PVA degrader namely Candida Sp. and Pseudomonas Sp., which were responsible for symbiotic degradation of chemical oxidation demand (COD) and PVA from desizing wastewater. In the process optimization, the maximum aeration was essential to achieve a high degradation rate, where as stirring enhances further degradation and foam control. Batch experiments concluded with the need of 16 lpm/l and 150 rpm of air and stirring speed respectively for high rate of COD and PVA degradation. Optimized process leads to 2 days of hydraulic retention time (HRT) with 85–90% PVA degradation. Continuous study also confirmed above treatment process optimization with 85.02% of COD and 90.3% of PVA degradation of effluent with 2 days HRT. This study gives environment friendly and cost effective solution for PVA containing textile wastewater treatment.

Relationships Between Soluble and Sediment Nutrient Losses, Land Use and Types of Soil in Agricultural Watersheds

1977 ◽  
Vol 12 (1) ◽  
pp. 121-134 ◽  
Author(s):  
G.H. Neilsen ◽  
A.F. Mackenzie
Keyword(s):  
Land Use ◽  
Inorganic Nitrogen ◽  
High Surface ◽  
Sediment Concentration ◽  
Chemical Oxidation ◽  
Nutrient Loss ◽  
Potassium Sulfate ◽  
Agricultural Watersheds ◽  
Nutrient Losses ◽  
Calcium Magnesium

Abstract Seven agricultural watersheds in southwestern Quebec and southeastern Ontario, ranging in area from 2,000 to 20,000 hectares, were monitored systematically during 1973–75 for soluble inorganic nitrogen, total soluble phosphorus, calcium, magnesium, potassium, sulfate-sulfur, chemical oxidation demand, discharge, suspended sediment concentration, sediment Kjeldahl nitrogen, Bray extractable phosphorus, and ammonium acetate extractable calcium, magnesium and potassium. For 1974–75, annual Kg/ha, loss rates were calculated for the soluble and sediment associated nutrients. Losses varied with nutrient and watershed, with volume of runoff being an important control of nutrient loss variation. Significant amounts of SO4−S in precipitation were suggested by an average watershed soluble N:P:S loss ratio of 10:1:92. Sediment nutrient losses were especially important for N and P, comprising over 40% of their total loss. The importance of spring snow-melt runoff was demonstrated by the high proportion of all nutrients lost at this time. Correlations of nutrient loss, land use and soils suggested that certain land uses resulted in increased stream nutrient losses while increased watershed area of soils with a high surface runoff potential was particularly conducive to increased soluble nutrient and sediment losses.

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