Ti-MCM-41 materials synthesised at room temperature as catalysts for cyclisation of (±)-citronellal”

In the present work we extend the applicability of those Ti-MCM-41 materials, as heterogeneous catalysts, to produce an important intermediate, isopulegol, from the cyclisation of citronellal. The use of this kind of materials appears to be a good option over homogeneous catalysts, because they offer the advantage of recovery and, consequently, contribute to environmentally friendly processes

Modification and Optimization of Activated Carbons for Phenolic Compounds Removal

Phenols are generally considered to be one of the important organic pollutants discharged into the environment causing unpleasant taste and odour of drinking water. Development of inexpensive adsorbents from industrial wastes for the treatment of wastewaters is an important area in environmental sciences. For the phenolic compounds removal, it appears that the pH of the solution, the real surface area of the solid, and functional groups play a major role. The objective of this study was to screen various adsorbents for potential application for the removal of phenolic compounds for drinking water concentration range. The adsorbents used in this study were AC prepared from recycled PET and AC prepared from cork submitted to a reduction post treatment

An innovative approach to develop microporous activated carbons in oxidising atmosphere

The aim of the study was to investigate a rather oxidising atmosphere such as air for the development of a microporous activated carbon from demineralised kraft lignin. Demineralisation of lignin makes the precursor low in reactivity and hence can allow the use of more oxidising atmospheres. Control of the activation conditions allowed development of microporous activated carbons with type I N2 adsorption isotherms from demineralised kraft lignin having micropore volumes and mean micropore widths up to 0.374 cm3 g-1 and 1.12 nm, respectively. A unique feature of this study is to prepare high surface área (1305 m2 g-1) microporous activated carbon at a high temperature (950 ºC) in air atmosphere. The effect of temperature on the surface area, micropore volume, mean micropore width and total pore volume was also studied for the development of activated carbons from the precursor in the range 550-1050 ºC

Direct Nitrogen Enrichment of Activated Carbon Produced from Synthetic or Natural Precursor

The specific application of activated carbons (AC) as adsorbents for gases and vapours depends on the properties of pollutants to be removed, but the performance of the AC depends on various properties. If their porosity is the main parameter in gas adsorption, the chemical nature of their surface plays a significant role in liquid phase interactions and in their usefulness as catalyst support materials. Of particularly interest are the AC containing heteroatoms, such as oxygen, hydrogen, phosphorus, sulphur and nitrogen. Generally, the AC containing various nitrogen groups,present more basic character and increased adsorption of acidic agents is expected. These AC found widespread applications as adsorbents for hydrogen sulphide, sulphur dioxide, sulphur and carbon dioxide and as catalysts for selective oxidation of hydrogen sulphide

Using Waste Recycled PET for AC Production for Pesticides Removals from Aqueous Solutions

Over the last decades the literature has shown the possibility of producing activated carbons (AC) from a wide variety of raw materials and to use them as one of the most environment-friendly solutions for waste disposal. Additionally it has been shown that the adsorption of pollutants from different media by AC is one of the most efficient techniques for remediating or solving this type of problem. In this context, the presence of pesticides in water can cause serious problems in the environment and to human health; their removal from wastewaters is a crucial concern. The work presented here focuses these two problematic areas (solid waste reduction and wastewater treatment). The main idea was to develop low cost and efficiently adsorbent materials for hazardous compounds removal from aquatic media, to level admitted in drinking water

Activated Carbon Post Treatment - Influence on Phenolic Compounds Removal

● AC preparation from different precursors and their modification / optimisation with sodium hydroxide and urea to improve the adsorption capacities for phenolic compounds from the liquid phase. ● Comparative study of the influence of textural and chemical parameters of AC on the liquid phase adsorption

Porosity of clay catalysts for biomass conversion: a comparative study

A detailed description of the porosity, in particular of microporosity, was reported and allowed a clear comparison of the effects on the porosity of chemical treatments on clays from the Source Clays Repository (USA) and SD clay from Porto Santo (Portugal)

Modification and Optimization of Activated Carbons for Phenolic Compounds removals

Phenols are generally considered to be one of the important organic pollutants discharged into the environment causing unpleasant taste and odour of drinking water. Development of inexpensive adsorbents from industrial wastes for the treatment of wastewaters is an important area in environmental sciences. For the phenolic compounds removal, it appears that the pH of the solution, the real surface area of the solid, and functional groups play a major role. The objective of this study was to screen various adsorbents for potential application for the removal of phenolic compounds for drinking water concentration range. The adsorbents used in this study were AC prepared from recycled PET and AC prepared from cork submitted to a reduction post treatment

Modification and Optimization of Activated Carbons for Phenolic

Phenolic compounds are generally considered to be one of the important organic pollutants discharged into the environment causing unpleasant taste and odour of drinking water [1,2]. So, removal of phenolics compounds from industrial effluents is required before sewage disposal. The development of inexpensive adsorbents from industrial wastes for the treatment of wastewaters is an important area in environmental sciences. For the phenolic compounds removal, it appears that the pH of the solution, the real surface area of the solid and functional groups play a major role. Adsorption onto activated carbons (AC) is often considered, amongst the methods currently employed to remove inorganic and organic pollutants, from aqueous or gaseous phases, as the most efficient and one of the most economical. A detailed characterization of physical and chemical surface properties of an AC has become one of the most important issues in adsorption technology because it ascertain its suitability for one or more of the application fields

The influence of the activated carbon post-treatment on the phenolic

The aim of this research was to investigate how post treatment modification, such as those with sodium hydroxide or urea, can influence the capacity of activated carbon (AC) for phenolic compounds removal from liquid media. The ACs modification was performed using urea impregnation followed by pyrolysis at high temperature. With all ACs used, this treatment induced a pore volume increase, a mean pore size broadening, an increase in the point of zero charge and also in the basic character. The modification with sodium hydroxide brings to light the influence of the precursor nature as the achievements are really diverse. With the ACs obtained from PET, a pore volume and mean pore size reduction occurred, with the AC-cloth no textural effect was observed and with the AC obtained from cork, an enlargement of the mean pore size and an increase of the pore volume were confirmed. The difference in the acidic/basic character exhibited by the modified ACs was in agreement with the presence of acidic/basic superficial groups identified by FTIR. The textural and chemical properties of the ACs affect in a direct way the phenolic compounds removal capacity. Particularly, those modified with urea, which exhibited a superior removal capacity for both phenolic compounds