Bio-based functionalized adsorptive polymers for sustainable water decontamination: A systematic review of challenges and real-world implementation

The overwhelming concerns of water pollution, industrial discharges and environmental deterioration by various organic and inorganic substances, including dyes, heavy metals, pesticides, pharmaceuticals, and detergents, intrinsically drive the search for urgent and efficacious decontamination techniques. This review illustrates the various approaches to remediation, their fundamentals, characteristics and demerits. In this manner, the advantageous implementation of nature-based adsorbents has been outlined and discussed. Different types of lignocellulosic compounds (cellulose, lignin, chitin, chitosan, starch) have been introduced, and the most used biopolymeric materials in bioremediation have been highlighted; their merits, synthesis methods, properties and performances in aqueous medium decontamination have been described. The literature assessment reveals the genuine interest and dependence of academic and industrial fields to valorize biopolymers in the adsorption of various hazardous substances. Yet, the full potential of this approach is still confined by certain constraints, such as the lack of reliable, substantial, and efficient extraction of biopolymers, as well as their modest and inconsistent physicochemical properties. The futuristic reliance on such biomaterials in all fields, rather than adsorption, is inherently reliable on in-depth investigations and understanding of their features and mechanisms, which can guarantee a real-world application and green technologies.

A Novel Approach for Therapeutic Drug Monitoring of Valproic Acid Using FT-IR Spectroscopy and Nonlinear Support Vector Regression

BACKGROUND

Recent technological progress has bolstered efforts to bring personalized medicine from theory into clinical practice. However, progress in areas such as therapeutic drug monitoring (TDM) has remained somewhat stagnant. In drugs with well-known dose-response relationships, TDM can enhance patient outcomes and reduce health care costs. Traditional monitoring methods such as chromatography-based or immunoassay techniques are limited by their higher costs and slow turnaround times, making them unsuitable for real-time or onsite analysis.

OBJECTIVE

In this work, we propose the use of a fast, direct, and simple approach using Fourier transform infrared spectroscopy (FT-IR) combined with chemometric techniques for the therapeutic monitoring of valproic acid (VPA).

METHOD

In this context, a database of FT-IR spectra was constructed from human plasma samples containing various concentrations of VPA; these samples were characterized by the reference method (immunoassay technique) to determine the VPA contents. The FT-IR spectra were processed by two chemometric regression methods: partial least-squares regression (PLS) and support vector regression (SVR).

RESULTS

The results provide good evidence for the effectiveness of the combination of FT-IR spectroscopy and SVR modeling for estimating VPA in human plasma. SVR models showed better predictive abilities than PLS models in terms of root-mean-square error of calibration and prediction RMSEC, RMSEP, R2Cal, R2Pred, and residual predictive deviation (RPD).

CONCLUSIONS

This analytical tool offers potential for real-time TDM in the clinical setting.

HIGHLIGHTS

FTIR spectroscopy was evaluated for the first time to predict VPA in human plasma for TDM. Two regressions were evaluated to predict VPA in human plasma, and the best-performing model was obtained using nonlinear SVR.

Adsorption of cationic and anionic dyes onto coffee grounds cellulose/sodium alginate double-network hydrogel beads: Isotherm analysis and recyclability performance

This work describes the preparation of new eco-friendly adsorbents with a simple method. Gel beads of coffee grounds cellulose (CGC) and sodium alginate (SA) were prepared for wastewater treatment. Upon their synthesis, the physicochemical properties, performances and efficiency were analyzed by means of various structural and morphological characterizations. Kinetic and thermodynamic adsorption approaches evaluated the removal capacity of these beads which reached equilibrium in 20 min for Methylene Blue (MB) and Congo Red (CR). Also, the kinetics shows that the results can be explained by the pseudo-second-order model (PSO). Furthermore, the isotherm assessments showed that Langmuir-Freundlich can fit the adsorption data of both contaminants. Accordingly, the maximum adsorption capacities reached by the Langmuir-Freundlich model are 400.50 and 411.45 mg/g for MB and CR, respectively. It is interesting to note that the bio-adsorption capabilities of MB and CR on bead hydrogels decreased with temperature. Besides, the results of the thermodynamic study evidenced that the bio-adsorption processes are favorable, spontaneous and exothermic. The CGC/SA gel beads are therefore outstanding bio-adsorbents, offering a great adsorptive performance and regenerative abilities.

Biopolymer-Modified Carbon Paste Electrode for the Electrochemical Detection of Pb(II) in Water

During the present study, biopolymer lignin was extracted, in particular, from sugar beet pulp (molasses) from the Tadla region (224 km from Marrakech, Morocco). The lignin was characterized by infrared spectroscopy (FTIR) and thermogravimetric TG/DTA analysis and then used as a modifier to enhance the electroanalytical detection of heavy metal ion traces. The performance of the lignin/CPE sensor to detect lead (II) was studied by cyclic voltammetry (CV) and square-wave voltammetry in 0.3 mol L^-1 NaCl. With optimized experimental parameters, the lignin/CPE sensor developed has a minimum detection limit of 2.252.10^-11 M for Pb (II). The proposed working electrode has been successfully applied for the coanalysis of Pb (II) in tap water with good results.

Comparative study of three fingerprint analytical approaches based on spectroscopic sensors and chemometrics for the detection and quantification of argan oil adulteration

BACKGROUND

Argan oil is one of the purest and rarest oils in the world, so that the addition of any further product is strictly prohibited by international regulations. Consequently, it is necessary to establish reliable analytical methods to ensure its authenticity. In this study, three multivariate approaches have been developed and validated using fluorescence, UV-visible, and attenuated total reflectance Fourier transform mid-infrared (FT-MIR) spectroscopies.

RESULTS

The application of a partial least squares discriminant analysis model showed an accuracy of 100%. The quantification of adulteration have been evaluated using partial least squares (PLS) regression. The PLS model developed from fluorescence spectroscopy provided the best results for the calibration and cross-validation sets, as it showed the highest R² (0.99) and the lowest root mean square error of calibration and cross-validation (0.55, 0.79). The external validation of the three multivariate approaches by the accuracy profile shows that these approaches guarantee reliable and valid results of 0.5-32%, 7-32%, and 10-32% using fluorescence, FT-MIR and UV-visible spectroscopies respectively.

CONCLUSION

This study confirmed the feasibility of using spectroscopic sensors (routine technique) for rapid determination of argan oil falsification. © 2021 Society of Chemical Industry.

Molecular docking, spectroscopic studies and simulation of the dopamine molecule by the DFT and MP2 methods

The FTIR and Raman spectra of dopamine were also recorded in the spectral region 20 - 4000 cm-1 and 400 - 4000 cm-1 respectively. The optimized molecular geometry and fundamental vibration frequencies are interpreted using structural optimizations based on the DFT method. The B3LYP / 6-311G (d, p) was used to determine the calculations of the chemical descriptor. The dopamine (DA) molecule can acquire a maximum charge of 0.513 eV from its environment. To understand the molecular interactions of Dopamine, the MEP is a crucial tool. Nonlinear optical descriptors (NLO) and the lengths, bond angles are also determined by DFT and MP2 methods. The DFT method was used to determine the chemical shifts of 1H and 13C of the product. These constants have been calculated by employing the GIAO (Gauge-Including-Atomic-Orbit), CSGT (Continuous Set of Gauge Transformations) and IGAIM (Individual Gauges for Atoms In Molecules) methods at the B3LYP/6-311G (d, p). The comparison of the theoretical chemical shifts with the experimental ones shows that the CSGT method is the best.

Theoretical study of the stability and reactivity of salicylic acid isomers by the DFT method

The FT-IR spectrum of salicylic acid (SA) was studied in the region 10-4000 cm-1. The optimized molecular geometry and fundamental vibration frequencies are interpreted using structural optimizations based on the Functional Density Theory (DFT) method. Additionally, we used B3LYP / 6-311G (d, p) to determine the chemical descriptor, the ionization potential (I), the electron affinity (A), the chemical potential (μ), the chemical hardness (η). Nonlinear optical descriptors (NLO) such as dipole moment (μ), polarizability (α), first hyperpolarizability (β) and second hyperpolarizability (γ), 3D maps of HOMO and LUMO orbitals, lengths and Bond angles of salicylic acid isomers are also determined by both DFT and MP2 (The Møller-Plesset theory of order 2 perturbation) methods. The overall descriptors and the non-linear optical properties confirmed that salicylic acid is the reactive molecule and para-hydroxybenzoic acid is the stable molecule. An electrostatic molecular potential (MEP) study was also performed to determine the reactivity of molecules.

Rapid Analytical Method to Characterize the Freshness of Olive Oils Using Fluorescence Spectroscopy and Chemometric Algorithms

One of the most important issues in the field of quality assurance of olive oils is the detection of the freshness of olive oil. In this study, 400 nm laser-induced fluorescence spectroscopy was used with supervised and unsupervised multivariate analysis methods to develop a rapid method able to discriminate between freshly produced olive oils and oil that has been stored for a period of time ranging from 12 to 24 months. The fluorescence spectral data were firstly processed by the PCA. This method shows strong discrimination of the three oil classes using the first three components which present 96% of the total variability of the initial data, and then supervised classification models were constructed using the discriminant partial least square regression PLS-DA, support vector machine SVM, and linear discriminant analysis LDA. These methods show a high capacity in the classification of the three classes of olive oil. The validation of these classification models by external samples shows a high capacity of classification of the samples in their class with an accuracy of 100%. This study demonstrated the feasibility of the fluorescence spectroscopy fingerprint (routine technique) for the classification of olive oils according to their freshness and storage time.

Corrigendum to: Quantum-chemical Ab Initio Calculations on the Donor–Acceptor Complex Pyridine–Borabenzene (C5H5N–BC5H5)

The adduct of borabenzene (C5H5B) and pyridine (C5H5N) was studied by means of quantum-chemical ab initio and time-dependent density functional theory calculations at different levels of theory. In the fully optimized structure (MP2/6-311++G**) of the free donor–acceptor complex (C2), the C–B–C angle amounts to 120.6°. The planes of the two aromatic rings enclose a torsion angle of ~40° with a barrier to rotation about the B–N bond of less than 3kcalmol–1 (1kcalmol–1=4.186kJmol–1). The highest computational level applied in this study (complete basis set limit, coupled cluster with single and double excitations (CCSD)) results in an energy associated with the reaction of borabenzene with pyridine of –52.2kcalmol–1. Natural bond orbital analyses were performed to study the bond between the borabenzene and the pyridine unit of the adduct. The UV-vis spectrum of the adduct was calculated employing time-dependent density functional theory methods and the symmetry-adapted cluster-configuration interaction method. Our calculated electronic excitation spectrum of the pyridine adduct as well as its spectrum of the normal modes qualitatively reproduce the characteristic features of the IR and the UV-vis spectra described by experimentalists and thus allows assignment of the observed absorption bands, which in part agree with those by other authors.

Study of spontaneous crystalluria on a series of patients in the Tadla Azilal Moroccan area

OBJECTIVES

There are few studies on crystalluria in the developing countries. The aim of the present study was carrying out a first study in Morocco on the frequency and the chemical nature of the crystalluria according to the sex and the age of human individuals living in the Tadla Azilal moroccan area.

METHOD

200 samples resulting from the morning urines of morning fasting individuals of the two sexes and different ages were collected. The pH was measured by a portable pH-meter "Pocket pH-meter ad 170 pH". The identification of the chemical nature of the crystalluria was carried out using a polarized light microscope "Olympus BX41". Such identification was based on morphology, polarization, and the pH of the urinary crystals.

RESULTS

In this series the positive frequency of crystalluria was 25.4% and was distributed on 3 age groups so that 27.9% in the youngest group, 32.6% in the middle aged group and 39.5% in the oldest one. The distribution on the sex is such as 53.4% in the man and 46.5% in the woman. A large majority (83.7%) of the crystalluria consists of homogeneous crystalluria. In the man, the Weddellite is dominant (69.6%) in the crystalluria while in the woman the Weddellite yields the place to the two phases of the uric acid (60%).

CONCLUSIONS

The studied series presents a non high frequency of crystalluria, which increases with the age. The factor sex has weakly increased the frequency of crystalluria in the man compared to the woman. The oxalocalcic nature is dominant in the crystalluria resulting from the man while it is the uric nature that is so in the woman. Other studies are necessary to be able to understand the etiology of a such difference, in the chemical nature of the crystalluria, between the two sexes.

In vitro and in vivo study of effect of lemon juice on urinary lithogenesis

OBJECTIVES

The diversity of experimental results obtained in the study of the effect of citrus juice on urinary lithogenicity moved us to study the effect of these substances in vitro and in-vivo. The in-vitro study is based on the turbidimetric method on calcium oxalate crystallization. In vivo, we studied the effect of lemon juice consumption on urinary chemistry and we tested it on calcium oxalate crystallization in natural urine.

METHODS

The formation of crystals is induced by the addition of the oxalate and calcium solution. Optical density (OD) is measured in a closed system at physiological conditions. The effects of the various juices of lemon, was evaluated by the addition of 50 ml of juice. A male volunteer with no history of kidney stone participated in this study, by lemon juice ingestion. The pH, concentration of oxalate, calcium and citrate were determined before and after ingestion and urine was freshly analyzed by microscopy.

RESULTS AND CONCLUSIONS

In synthetic urine, the inhibition rate of calcium oxalate crystallization increases gradually with the lemon juice concentration. In natural urine, we noted that the kinetics of crystallization of calcium oxalate, before and after ingestion of lemon juice, are comparable. In vivo, after ingestion, a small increase in mean urinary pH (from 6.7 +/- 0.1 to 6.9 +/- 0.1) was noted. Indeed, oxalate calcium means and citrate excretion increased during this period with 33.41%, 6.85% and 3.53% respectively. This increase in the oxalate excretion is probably explained by the conversion of the exogenous ascorbic acid contained in the lemon juice. These results show that the lemon juice presents an important inhibitory effect in vitro. The ingestion of the lemon juice seems to dissipate a effect of great quantity of citrates which in turn increases the excretion of oxalates. The presence of these two elements simultaneously: citrate and oxalate compensate for their opposite effect.

[Study of crystalluria in diabetic patients]

INTRODUCTION

The incidence of diabetes, particularly non-insulin-dependent diabetes, is on the increase in industrialized and developing countries. The prevalence of renal stones in the diabetic population was recently estimated to be 21%, i.e. more than twice the prevalence of stones in the general population. Other studies have emphasized the high frequency of uric acid stones in this particular population. The present study was designed to verify whether diabetic patients present a particular type of crystalluria predisposing them to a high frequency of uric acid stones than other types of stones, which could allow detection of this risk and the proposal of therapeutic measures to prevent these stones.

MATERIAL AND METHOD

The first morning urine of 208 diabetic patients was examined by polarized light microscopy to detect and identify crystalluria. Patients were distributed into 3 age-groups: less than 40 years, 40 to 59.9 years and 60 years or more. The results are expressed as the predominant crystalline species.

RESULTS

The overall frequency of crystalluria was 29.8%, i.e. about one half that observed in calcium stones. However, the crystallogenic profile was very unusual, as 61.3% of cases of crystalluria consisted of purine. Uric acid crystalluria was twice as frequent in women than in men (66% vs 33.3%, p < 0.05). The mean pH of the urine of diabetic subjects was 5.5, i.e. significantly more acidic than that of normal subjects or patients with calcium stones. pH was negatively correlated with the patient's age, decreasing from 5.54 in patients younger than 40 to 5.3 in patients over the age of 60 (p < 0.05). The mean pH of crystalluric urine was significantly more acidic than that of crystal-free urine (pH 5.2 +/- 0.46 vs 5.5 +/- 0.67, p < 0.01).

CONCLUSION

Diabetic patients have an acidic urinary pH which tends to decrease with age, predisposing to uric acid crystalluria, which is particularly frequent in women. The high prevalence of uric acid crystalluria and the high proportion of uric acid stones reported in diabetic women suggest that women are at greater risk than men of developing uric acid stones in the context of diabetes. The study of crystalluria could be useful to detect this risk and to propose preventive measures. Complementary studies are necessary to identify factors accounting for the increased risk of uric acid stones in diabetic women and to verify whether good glycaemic control can reduce the crystallogenic risk.