In situ ATR-FTIR Spectroscopy for Functional Groups of Humic Substances Complexing with Metal Ions

This research programme is concerned with the uptake studies of Cu2+, Zn2+ and Mn2+ at different conditions, by merino wool fibres and also uptake studies of Cu2+ ions by chemically modified wool fibres. Cu2O particles and Cu complexes are formed within merino wool by an in situ reaction with sodium borohydride and thioglycoloic acid respectively. The d-block elements have the ability to bind chemically to certain functional groups present within the keratin protein of wool. The absorption of the Cu2+, Mn2+ and Zn2+ from solution by wool fibres under different conditions notably, time, temperature and initial concentration have been studied. The optimum temperature and reaction time to give highest absorption of the Cu2+ by the wool fibre was found to be 90 oC and one hour without modifying the nature of the wool, from a solution of Cu2+ concentration of 450 mg L-1. Cu2+ was found to give the greatest absorption by the wool fibres, whereas Zn2+ and Mn2+ were found to be absorbed the least. The absorption of Cu2+ ions increases with increasing temperature. At the higher temperature of 90 oC, the -S-S- bonds in the cystine amino acids break more readily, generating thiol and cysteic acid groups to bind with copper ions. The uptake of Cu2+ by ethylenediaminetetraacetic dianhydride (14 mg g-1 of wool) or thioglycolic acid (42.5 mg g-1 of wool) or sodium borohydride (41.8 mg g-1 of wool) treated merino wool fibres increases with respect to unmodified wool (8 mg g-1 of wool). NaBH4 treated merino wool reduces Cu2+ ions to Cu2O particles which form within the wool fibres by an in situ reaction. TGA treated merino wool provides additional functional groups to bind with copper ions and Cu2O particles also likely to be formed within TGA treated wool composites. The metal ions were absorbed into the fibres under various conditions and the extent of absorption was quantified. The form and binding of the Cu2O particles or Cu2+ ions onto the wool fibres are studied using UV-Visible, FTIR, XRD, SEM, EDS and TEM methods.

Download Full-text

MODIFICATION OF HUMIC SUBSTANCES FOR DEVELOPMENT OF MATERIALS FOR ENVIRONMENTAL TECHNOLOGIES

Environment Technology Resources Proceedings of the International Scientific and Practical Conference ◽

10.17770/etr2019vol1.4123 ◽

2019 ◽

Vol 1 ◽

pp. 101

Author(s):

Maris Klavins

Keyword(s):

Molecular Weight ◽

Metal Ions ◽

Humic Substances ◽

Functional Groups ◽

Metal Ion ◽

Spectral Characteristics ◽

Water Soluble ◽

13C Nuclear Magnetic Resonance ◽

Mobility Behaviour ◽

Derivatives Of

Humic substances are high molecular weight refractory polycationites formed during decay of living organic matter and through biosynthesis of low molecular weight organic substances (metabolites or decay products of living organisms). Presence of many functional groups in the structure of humic substances determines their ability to interact with metal ions forming stable complexes and influencing metal ion speciation in the environment and mobility, behaviour and speciation forms in the environment. Presently humic substances are a product of industrial scale and quantities in amounts of hundreds of tons are produced. The aim of this study is to analyse derivatization possibilities of humic substances. To achieve this aim derivatization of humic substances using acylation (at first introduction of acetylgroups, but also changing length acyl chains are considered) are used. Also alkylation is used. Mild oxidation can help to obtain modified products with reduced molecular weight. Another approach includes introduction of new functional groups and structures. To achieve this aim, conjugates with short peptides, amines and sugar derivatives using coupling with water-soluble carbodiimides are obtained. As basic characteristics elemental analysis as well as functional analysis have been used, supported with Fourier transform infrared (FTIR), 13C nuclear magnetic resonance spectrometry and other methods. Derivatives of humic substances containing sulpho, amino, and hydroxylgroups and thiolgroups were synthesized and their properties were analyzed in respect to their their elemental composition; functional group content changes in spectral characteristics. The derivatives of humic substances showed significant differences in the number and in ability to interact with the metal ions, which were reflected in their complexation properties towards metal ions. FTIR spectra gave evidence of the presence of metal ions, strongly bound and protected in inner sphere complexes. The obtained derivatives of humic substances can be used for remediation of environment contaminated with heavy metal ions.

Download Full-text

Characterization of Water Hyacinth Powder Using FTIR Spectroscopy and the Adsorption Behaviour of Pb2+, Cd2+, Zn2+, Ni2+ and Cr2+ in Aqueous Solution

Asian Journal of Applied Chemistry Research ◽

10.9734/ajacr/2020/v6i130151 ◽

2020 ◽

pp. 47-55

Author(s):

J. M. Munene ◽

J. O. Onyatta ◽

A. O. Yusuf

Keyword(s):

Absorption Band ◽

Metal Ions ◽

Ftir Spectroscopy ◽

Functional Groups ◽

Water Hyacinth ◽

Lead Ion ◽

Batch Adsorption ◽

Raw Water ◽

Broad Absorption Band ◽

Stretching Vibrations

The adsorption behavior of selected metal ions on water hyacinth powder was investigated by Fourier Transform Infrared (FTIR) spectroscopy. Water hyacinth powder was used as an adsorbent due to its popularity, low cost and ease of availability. Water hyacinth stems were dried and ground to a powder. Batch adsorption experiments were conducted at room temperature by adding known concentrations of Pb2+, Cd2+, Cr3+, Zn2+ and Ni2+ to 5 g of water hyacinth powder in different test tubes and allowed to stand for the same time respectively. Adsorption is one of the methods used to remove heavy metals from aqueous solutions and wastewaters. FTIR analysis was performed to identify the functional groups in the water hyacinth powder using the KBr disc method. The study showed a strong broad absorption band in the region of 3300-3200cm-1 which is characteristic of O-H stretching vibrations of the adsorbed water molecules at the surface of raw water hyacinth powder particles. Other peaks appeared at 1732cm-1 which corresponded to C=O stretching vibrations while the band at 1396cm-1 could be attributed to C-H bonds. The functional groups identified were: C-H; O-H; C=O or C-O. After adsorption there was a disappearance, reduction or a shift in the adsorption bands depending on the type of metal ion. Lead for example showed a strong absorption band in the region of 1732cm-1 which is characteristic of C=O stretching bond structure which is found in esters and carboxylic acids. The disappearance of the peaks indicated that the H atom present in the functional groups of the raw water hyacinth powder could have been substituted with lead ion. The intensity of the adsorption bands reduced for all the metals confirming that functional groups were responsible for adsorption of the heavy metal ions on to the material.

Download Full-text

Some Uptake Studies of Metal Ions and the Formation of Cu₂0 Particles in Wool

10.26686/wgtn.17004106 ◽

2021 ◽

Author(s):

◽

Ishira Samarasinghe

Keyword(s):

Metal Ions ◽

Functional Groups ◽

Sodium Borohydride ◽

Copper Ions ◽

Cysteic Acid ◽

Wool Fibre ◽

In Situ Reaction ◽

Merino Wool ◽

Uptake Studies

This research programme is concerned with the uptake studies of Cu2+, Zn2+ and Mn2+ at different conditions, by merino wool fibres and also uptake studies of Cu2+ ions by chemically modified wool fibres. Cu2O particles and Cu complexes are formed within merino wool by an in situ reaction with sodium borohydride and thioglycoloic acid respectively. The d-block elements have the ability to bind chemically to certain functional groups present within the keratin protein of wool. The absorption of the Cu2+, Mn2+ and Zn2+ from solution by wool fibres under different conditions notably, time, temperature and initial concentration have been studied. The optimum temperature and reaction time to give highest absorption of the Cu2+ by the wool fibre was found to be 90 oC and one hour without modifying the nature of the wool, from a solution of Cu2+ concentration of 450 mg L-1. Cu2+ was found to give the greatest absorption by the wool fibres, whereas Zn2+ and Mn2+ were found to be absorbed the least. The absorption of Cu2+ ions increases with increasing temperature. At the higher temperature of 90 oC, the -S-S- bonds in the cystine amino acids break more readily, generating thiol and cysteic acid groups to bind with copper ions. The uptake of Cu2+ by ethylenediaminetetraacetic dianhydride (14 mg g-1 of wool) or thioglycolic acid (42.5 mg g-1 of wool) or sodium borohydride (41.8 mg g-1 of wool) treated merino wool fibres increases with respect to unmodified wool (8 mg g-1 of wool). NaBH4 treated merino wool reduces Cu2+ ions to Cu2O particles which form within the wool fibres by an in situ reaction. TGA treated merino wool provides additional functional groups to bind with copper ions and Cu2O particles also likely to be formed within TGA treated wool composites. The metal ions were absorbed into the fibres under various conditions and the extent of absorption was quantified. The form and binding of the Cu2O particles or Cu2+ ions onto the wool fibres are studied using UV-Visible, FTIR, XRD, SEM, EDS and TEM methods.

Download Full-text

On the adsorption and reduction of NO−3 ions at Au and Pt electrodes studied by in situ FTIR spectroscopy

Journal of Electroanalytical Chemistry ◽

10.1016/s0022-0728(96)04697-9 ◽

1996 ◽

Vol 414 (2) ◽

pp. 163-170 ◽

Cited By ~ 27

Author(s):

M.C.P.M. da Cunha ◽

M. Weber ◽

F.C. Nart

Keyword(s):

Ftir Spectroscopy ◽

In Situ Ftir ◽

Reduction Of No ◽

In Situ Ftir Spectroscopy ◽

Pt Electrodes

Download Full-text

Reductive Cleavage of Secondary Sulfonamides: Converting Terminal Functional Groups into Versatile Synthetic Handles

10.26434/chemrxiv.9925145 ◽

2019 ◽

Author(s):

Patrick Fier ◽

Suhong Kim ◽

Kevin M. Maloney

Keyword(s):

Functional Groups ◽

Late Stage ◽

Reductive Cleavage ◽

Bioactive Molecules ◽

General Method

Sulfonamides are pervasive in drugs and agrochemicals, yet are typically considered as terminal functional groups rather than synthetic handles. To enable the general late-stage functionalization of secondary sulfonamides, we have developed a mild and general method to reductively cleave the N-S bonds of sulfonamides to generate sulfinates and amines, components which can further react in-situ to access a variety of other medicinally relevant functional groups. The utility of this platform is highlighted by the selective manipulation of several complex bioactive molecules.

Download Full-text