Smart polymer hydrogels with superior dye adsorption (brilliant green) characteristics were synthesized via freeradical polymerization by grafting acrylic acid segments onto allylated chitosan and inducing crosslinking with a trimethylolpropane triacrylate crosslinker. The synthesized adsorbents were characterized for their chemical structure (FT-IR and 1H NMR), thermal stability (TG/DTG), and morphological features (SEM). The adsorption capacity for brilliant green (934 mg/g) and water uptake (712 g/g) were determined using spectrophotometric and gravimetric methods, respectively. The interaction between the synthesized adsorbent and brilliant green, including potential dye orientation on the adsorbent and hydrogen bond formation was analyzed using Density Functional Theory. The maximum adsorption of brilliant green (934 mg/g) and water uptake was achieved by optimizing the monomer feed compositions. Adsorption studies revealed that dye uptake followed Fickian diffusion and the Langmuir isotherm model, with pseudo-second-order kinetics. Thermodynamic analysis demonstrated that the adsorption process was spontaneous and exothermic, as evidenced by changes in free energy, enthalpy, and entropy under varying temperatures. Theoretical investigations confirmed the excellent affinity of the synthesized adsorbent toward brilliant green. Furthermore, reusability studies showed that the adsorbent retained its dye-holding capability over 20 adsorption-desorption cycles, highlighting its potential for sustainable and efficient dye removal applications.

This study investigated the effectiveness of 2, 6-bis-furan-2ylmethylene-cyclohexanone as a corrosion inhibitor for carbon steel in a 0.5 M HCl solution through a combination of experimental and theoretical methodologies. Firstly, the study employs weight loss analysis, revealing that the presence of 0.10 ppm of the inhibitor leads to a significant inhibition efficiency (IE) of 93.40% against corrosion in acidic conditions. Polarization studies further elucidate the inhibitor's role, indicating its function as a cathodic inhibitor and its influence on the corrosion kinetics of carbon steel. Moreover, alternating current impedance spectra are analysed to gain insights into the electrical behaviour of the protective film formed by the inhibitor and its consequent impact on the corrosion resistance of carbon steel. The composition of this protective film, comprising both carbon steel and 2, 6-bis-furan-2ylmethylene-cyclohexanone was confirmed using advanced imaging techniques such as scanning electron microscopy (SEM) and atomic force microscopy (AFM). In addition to experimental investigation, a theoretical approach was also employed using Density Functional Theory (DFT) to predict the behaviour of the inhibitor at the molecular level on the surface of carbon steel. This theoretical framework facilitates a deeper understanding of the interactions between inhibitor molecules and the carbon steel surface, offered insights into the mechanisms underlying the corrosion inhibition process. By utilizing quantum chemical calculations, the study aims to elucidate the inhibitory properties of 2,6-bis-furan-2ylmethylene-cyclohexanone against corrosion of carbon steel, thereby contributing to the development of effective corrosion inhibition strategies.

Water is the most essential resource for the biotic and abiotic components of an ecosystem. Any change in the quality of this water may cause adverse impact on the ecosystem. Hexavalent chromium is one such important pollutant that gets exposed in the water mainly through anthropogenic processes. Adsorption is considered to be an effective, economic and easiest method for remediation of such pollutants. Amongst the innumerable adsorbents available, biopolymers fetch the interest due to its cost effectiveness, efficiency and biocompatibility. But, the mechanical strength and workability of such biopolymers makes it unfit to use as an adsorbent. To improve these drawbacks, synthesis of biopolymeric composites become the need of the hour. So, an attempt was made here to synthesize metal cross-linked binary bio-composites using Alginate and Chitosan polymer matrix. Synthesized bio-composites were characterised with the aid of FTIR, XPS, Thermal analysis, SEM with EDAX and subjected for hexavalent chromium removal from water. Analysis of variance (ANOVA) with 95 % confidence intervals was used to assess the significance of independent variables and their interactions. Adsorption studies were done using batch process and to achieve greater sorption, various influencing parameters were optimized one by one. While investigating one parameter, other parameters were kept unaltered. Optimization was done for the parameters like contact time, dosage of the adsorbent, pH of the medium and presence of co-ions. Contact time and dosage for all the composites was 30 mins and 0.1 g respectively. Amongst the composites, Zirconium loaded binary composite possess high sorption capacity of around 14.8 mg/g. While Calcium and Iron loaded composites exhibit sorption capacity of around 9.8 mg/g and 10.4 mg/g respectively. Presence of other co-ions in the medium doesn't affect the sorption process. Isothermal studies infer the adsorption follows Langmuir model and thermodynamic parameters concludes the endothermic and randomness of the adsorption. The bio-composites can be recycled and used upto three cycles. Field trial was conducted and the composites work well in such conditions.

Researchers have shown considerable interest in the environmentally friendly synthesis of several nanoparticles particularly metal nano particles due to their multifaceted applications. The target of the current research includes the synthesis of nickel oxide nanoparticles (NiO-NPs) through the green route using the bark extract from Acacia Nilotica, and analyzed their chemical and surface morphological features using XRD, SEM, EDX, IR, UV-vis and photoluminescence spectroscopy. In addition, the corrosion inhibition ability and antimicrobial activity of the extract were also studied. The XRD analysis indicated that the NiO exist in the form of nanoparticles. It showed the formation of pure cubic NiO-NP with a prominent peak at 43.28 degrees reflected from the plane (200). The crystallite size was found to be 15.83 nm. The SEM micrographs revealed that NiO-NPs appeared to be a bulk cluster-like structure on their surface.The EDX analysis displayed the presence of Ni and oxygen atoms. The photoluminescence spectrum demonstrated that the green synthesized metal oxide nanoparticles have a modified emission band due to the presence of oxygen deficiencies and induced surface imperfections. The Fourier transform infrared spectroscopy (FTIR) confirmed the association of peaks with the C-H and Ni-O bonds. The UV-vis study showed a maximum absorption at 264 nm. A study on the inhibition efficiency towards microbes confirmed that the prepared NiO-NPs have a good inhibition against selected microbes such as S. aureus, E. coli, Candida albicans, A. Niger. The mass loss system showed restraint 93.68 % effectiveness in the mild steel, and the electrochemical study supported the formation of a defensive protective layer on the cathodic locales of the carbon steel surface inhibiting corrosion.

A series of smart polymer hydrogels with good uptake and controlled release characteristics were synthesized free-radically by growing poly(acrylic acid) on allylated guar gum using ammonium persulfate as an initiator and trimethylolpropane triacrylate as the crosslinker. The synthesized hydrogels were evaluated using FT-IR and NMR for their structure, thermo-gravimetric analysis (TG) to measure thermal stability, and scanning electron microscopy (SEM) to analyze surface morphology and swellability by gravimetric method under different pH and temperature conditions. The soil moisture content and gel fractions were measured using gravimetric methods. Additionally, a theoretical investigation was also performed to assess the urea-holding capacity of the synthesized hydrogel matrix using density functional theory (DFT) calculations. The uptake study revealed that the hydrogel with optimized monomer feed composition absorbed 851 g/g of water, 78 % and 67 % of urea from 0.5 % and 1 % urea solutions respectively under ambient conditions. The release study showed that 56 and 47 % of absorbed urea were released over 15 days from the urea-loaded hydrogels (0.5 % and 1 % urea solutions respectively). The uptake mechanism obeyed the non-Fickian and first-order kinetics models. The experimental evaluation and DFT calculations conveyed that the synthesized hydrogel could act as a candidature matrix for the controlled release of water and fertilizer in the agricultural field.

In the present investigation, the corrosion tendency of mild steel under acidic pH was studied by employing unused expired amiodarone (EAD) drug as a potential corrosion inhibitor by adopting the weight loss measurement method. The corrosion inhibition efficiency (IE) of the formed protective film (EAD) on the steel surface was analyzed using potentiodynamic polarization and AC-impedance spectroscopy studies. The surface morphology of the mild steel before and after corrosion (in 1.0 M HCl) was analyzed via scanning electron microscopy–energy dispersive X-ray spectroscopy (SEM–EDAX), atomic force microscopy (AFM), and thermodynamic studies. The weight loss measurement under different concentrations of EAD indicated that an excellent inhibition was displayed at a concentration of 0.001 M, and the IE was found to depend on both the concentration and molecular structure of EAD. A potentiodynamic polarization study revealed that EAD predominantly acted as a cathode inhibitor, and electrochemical impedance spectroscopy (EIS) confirmed the adsorption of EAD on the surface of mild steel, which obeyed Temkin’s adsorption isotherm model. The calculated thermodynamic parameters revealed that adsorption was spontaneous and exothermic.

The current research investigates the corrosion resistant efficiency of 2,4-diphenyl-3-azabicyclo[3.3.1] nonan – 9–one (PABN) as inhibitor in carbon steel in 0.5 M H2SO4 environment through experimental and theoretical approaches. The weight loss methodology demonstrates that 0.10 ppm of nonan-9-one compound effectively inhibits corrosion in carbon steel submerged in an acidic environment with an efficiency of inhibition as high as 97.2 %. The polarization studies reveals the function of the compound as an inhibitor at the anodic site, influencing the kinetics of carbon steel corrosion effectively. Impedance spectra under alternating current conditions elucidate the influence of the protective film formed by the action of PABN compound on the electrical behavior and corrosion resistance in carbon steel material. This existence of the protective film composed of carbon steel and PABN compound is affirmed through different techniques such as SEM, EDX and AFM. The DFT analysis anticipates the interaction patterns of the inhibitor with the surface of carbon steel using quantum chemical calculations, analyzing the molecular interactions between the molecules of the inhibitor and the surface of carbon steel, providing insights into PABN's corrosion inhibitory properties.

Development of new organic synthetic methods fascinating the researchers which facilitating the increasing demands of the modern society, environmental friendly with high efficiency and low cost. The introduction of chromophores in an organic molecules facilitating intersystem crossing (ISC) to harvest both singlet and triplet excitons is also currently demanding field. We report a facile synthesis of symmetrical azines from carbonyl compounds and hydrazine hydrate with carboxylic acid esters as catalyst in methanol. This reaction presents a condensation of primary amino groups in hydrazine hydrate and carbonyl compounds took place simultaneously in a very short refluxing time. The prepared azines 1-10 were structurally analysed by various analytical techniques such as LC-MS1, H NMR13, C NMR, UV-Vis, FTIR and single crystal X-ray diffraction. Photoluminescence properties of prepared azines were recorded in CCl4 at 1 x 10-3 M and excitation range from 329 to 362 nm. The photoluminescence analysis results revealed that compounds 1-10 (except 8) were showed delayed fluorescence and 8 was showed fluorescence property. The photophysical properties of compounds 1-10 such as electron density and band gap energies was calculated by density function theory. This results revealed that the intra-molecular charge transfer occurs within the azines. The azine function in the azines enabling intersystem crossing hence, it is showing phosphorescence.

Synthetic polymer hydrogels and modified natural polymer hydrogels are widely and increasingly used in agriculture, health care textiles, effluent treatment, drug delivery, tissue engineering, civil concrete structure, etc. Among them, the use of hydrogels in agricultural and horticultural sectors as matrices for the controlled release of water, various primary and secondary nutrients has drawn significant attraction from researchers, scientists, and industry persons due to their smartness with reference to controlled release characteristics based on plant requirement. Since the use of these hydrogels for controlled release application ensures the minimum utilization of water and plant nutrients in fields. Besides, this will bring down the overloading of fertilizer, soil contamination, and water pollution such as eutrophication, nitrate pollution, and micronutrient imbalance. This chapter is focused on the class of hydrogels that are used for the controlled release application in the agricultural and horticultural sectors as matrices, the possible methods of fine-tuning their structures for improving their fertilizer uptake and release behavior, safety aspects, and environmental issues.

A series of superabsorbent polymers (SAPs) were synthesized free-radically using hydroxyethyl methacrylate (HEMA), acrylic acid (AA) and its potassium salt, methacrylic acid (MAA) and its potassium salt as monomers, and N,N'-Methylenebisacrylamide (N,N-1-MBA) as crosslinker. The synthesized SAPs were evaluated for their chemical structure (FT-IR), thermal stability (TGA/DTG), surface morphology (SEM), and water, fertilizers uptake and release characteristics (swelling and deswelling). A SAP with the optimized composition of monomer and crosslinker had absorbed 898 g/g of water, and 68% of urea and 51% of potash from the 1% corresponding fertilizer solutions. The equilibrium swollen SAP had released the absorbed water completely over 21 days, but only 28% of potash and 43% of urea were released from the fertilizer-loaded SAPs under identical conditions with the same duration of release time. The water uptake followed Fickian diffusion mechanism for the optimized SAP. Thus obtained experimental results revealed that the synthesized SAP may be used as the matrix for the controlled release of water and fertilizers in the agricultural sector.

The present study involved in the synthesis of a series of hydrophilic crosslinked superabsorbent polymer (SAP) materials by free radical thermal copolymerization method using methacrylic acid (MAA), 2-hydroxyethyl methacrylate (HEMA), acrylamide (AM) as monomers and N,N1-methylenebisacrylamide (N,N1-MBA) as crosslinker. The structural (FT-IR), thermal stability (TGA/DTG), morphological features (SEM), water, fertilizer uptakes and release characteristics of synthesized SAPs were analyzed for field application. An optimized polymer composition had absorbed 839 g/g of water and it released the imbibed water over a period of 23 days. Fertilizer uptake investigation revealed that 85, 70 and 80% of urea, potash and superphosphate respectively were absorbed from their 1% solution and it had released only 33, 39 and 45% of urea, potash and superphosphate respectively at room temperature in a single absorption-desorption cycle. The results indicated that the obtained polymer may be used as matrix for the controlled release of water and fertilizers in agriculture sector.

The present work reports the complexation of few d-block metals with 3-hydroxy-2-naphthoic acid and guanidine which yields corresponding mononuclear complex bis(guaninium) 3-hydroxy-2-naphthoate metal (II) dihydrate of the type M(CN3H5)2{C10H6(3-O)(2-COO)}].2H2O, where M= form Mn(II), Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), Pb(II) and Ca(II) of ratio 1:2:4 – metal: acid: base. Characterization of the complexes were done by elemental analysis, IR spectra, UV-Visible spectroscopy, TG-DTA, powder XRD. TG-DTA study reveals various decomposition pattern and thermal stability of the metal complexes. Crystalline nature of the metal complexes is confirmed form powder XRD measurement. SEM coupled with EDAX and AFM confirms the presence of nano-sized metal oxides. Antibacterial studies of the metal complex prove that they are active against Bacillus subtilis and Escherichia coli. Furthermore, molecular docking was carried out for a study of physicochemical properties and to show the binding energy of ligands with proteins.

The present investigation is focused on the development of a series of hydrophilic smart polymer hydrogels using acrylic acid (AA) methacrylic acid (MAA), acrylamide (AM), 2-hydroxyethyl methacrylate (HEMA) as monomers and N,N1-methylenebisacrylamide (N,N1-MBA) as crosslinker. The structure, thermal stability and surface morphology of hydrogels were characterized by FT-IR, TGA/DTG and SEM respectively. An optimized copolymer composition had absorbed 654 g/g of water and it released the imbibed water over a period of 19 days. Besides, 88, 75 and 80% of urea, potash and superphosphate respectively were absorbed from their 1% solution and it had released only 37, 30 and 35% of these absorbed fertilizers. The results indicated that the obtained polymer may be used as matrix for the controlled release of water and fertilizers (plant nutrients) in agriculture sector. (c) 2021 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International Conference on Advances in Materials Research-2019.

The research work is oriented towards the preparation of an adsorbent carbon from Phyllanthus reticulatus plant to remove reactive orange 16 dye (RO 16) from aqueous media. The prepared carbon was activated (PRAC) using a mixture of nitric and phosphoric acids. The surface morphology and amorphous/crystalline nature of PRAC were assessed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) analysis respectively. The adsorption capacity of PRAC was measured by performing a batch mode adsorption study with reference to pH, temperature, PRAC dose and RO 16 concentration and the maximum dye adsorption was found to be 85.10%. The observed adsorption isotherm and kinetic model for the chosen adsorbent-adsorbate system seemed to be Langmuir and pseudo-second-order respectively. The measured changes that occurred in entropy (ΔSo), Gibbs free energy (ΔGo) and enthalpy (ΔHo) revealed that RO 16 uptake was spontaneous and exothermic.

The structure analysis of p-toluidinium picrate (PTP) crystal was performed by X-ray diffraction method and the spectral characterization was performed by FT-Raman spectroscopic technique. The optimization of PTP structure was carried out by using the four common functionals (B3LYP-D3BJ, B3LYP, CAM-B3LYP, and M05-2X). The obtained structural parameters were compared with the crystallographic data. The B3LYP-D361 functional was chosen for further analysis, since it allowed reliable reproduction of experimental bond lengths and angles (correlation coefficients > 0.98). The vibrational assignment of the fundamental modes was proposed on the basis of potential energy distribution (PED) calculations. The stability of the molecule due to hyper-conjugative interaction and charge delocalization was studied by natural bond orbital (NBO) analysis. The ultraviolet-visible (UV-Vis) spectrum of PTP was recorded in the region 200-600 nm and the electronic properties such as highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were measured by time-dependent density functional theory (TD-DFT) approach. The small energy gap between the HOMO and LUMO is an indicator of intramolecular charge transfer which is responsible for nonlinear optical (NLO) properties. The first order hyperpolarizability result confirmed the nonlinear optical activity of the molecule. Molecular electrostatic potential (MEP) analysis was performed to predict the reactive sites of the molecule. The theoretical results showed good agreement with the experimental values. The Hirshfeld surface analysis was made to find out the various intermolecular non-covalent interactions in the PTP molecule. (C) 2019 Elsevier B.V. All rights reserved.

Fe and Cu ions incorporated (Si/Cu = 50, Si/Fe = 50 and Si/Cu + Fe = 50) amorphous, wormhole structured mesoporous catalysts (CuTUD-1, FeTUD-1 and FeCuTUD-1) (TUD-1-Technische Universiteit Delft) have been synthesized hydrothermally using low cost, non-surfactant template triethanolamine (TEA). Physicochemical properties of the catalysts were made using X-ray diffraction (XRD), Nitrogen sorption, FT-IR, DRS UV Visible, FT Raman, SEM, TEM and TG-DTG techniques. The results showed that the materials possess mesoporous, foam type morphology, surface area 485-634 m(2)/g, pore size 4.8-6.8 nm, pore volume 0.67-0.83 cm(3)/g and metal ions (Cu2+ and Fe3+) coordinative environment. The highly dispersed Cu2+ and Fe3+ active sites are observed in FeCuTUD-1 catalyst. Also, the synthesized catalysts are tested in the oxidation of phenol with hydrogen peroxide (H2O2) oxidant. Further, reaction parameters such as time, temperature, and catalyst were also investigated.

Density functional theory (DFT) is implemented for analyzing the structural and mesogenic properties of the synthesized undecyloxy benzoic acid (11OBASA) with suberic acid mesogen (11OBASA). For the present study B3LYP level of theory is adopted with 6-311G (d, p) basis set for all the computations. The bond lengths and bond angles obtained from the optimized geometry and natural bond orbital analysis confirm the presence of intermolecular hydrogen bond. Chemical reactivity is studied by the simulation of molecular electrostatic potential surface, and the nematogen phase stability is determined through charge distribution of mesogen molecules. The mesogen characteristics have been established through global and local reactivity descriptors. Nonlinear optical properties and time-dependent-DFT investigations provide the physical properties of the synthesized mesogen.

The present study focused on the structural conformations, alkoxy chain lengths and mesogenic properties of two mole of alkoxy benzoic acid(nOBA) and one mole of suberic acid (SA) hydrogen bonded (nOBASA) complexes (n=8 to 10) by density functional theory (DFT) calculations and the Fourier Transform Infrared (FT-IR) spectrum. The intermolecular hydrogen bond formation was confirmed by the optimized geometric bond lengths and bond angles obtained by computation. Using the natural bond orbital (NBO) analysis, the stability of the molecule arising from hyper conjugative interactions and charge delocalization has been analyzed. Results obtained shows that the charge in electron density (ED) in sigma* and pi* antibonding orbital and second order delocalization energies E(2) authorizes the occurrence of intermolecular charge transfer. The molecular electrostatic potential (MEP) surface map is plotted over the optimized geometry of the molecule to obtain the chemical reactivity of the molecule. From the local charge distributions, the mesomorphic behavior and the nematic phase stabilities for each of the molecule have been predicted. Finally the calculated result is applied to simulated infrared spectra of 8OBASA mesogens which shows good agreement with the observed spectra. The comparison of the theoretical results obtained with the experimental ones shows the reliability of this DFT method.

In the present study structural effects of alkoxy chain lengths and mesogen properties of hydrogen bonded (nOBASA) complexes (n=5, 6, 7) have been studied by density functional theory (DFT) calculations and Fourier Transform Infrared (FT-IR) spectrum. The B3LYP/6-311G(d,p) level of theory has been adopted for all the computations. The experimental FT-IR (400-4000cm(-1)) spectrum was recorded on the solid phase of the molecule. The intermolecular hydrogen bond formation has been conformed from the optimized geometry. The vibrational assignments, highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energies were calculated. The stability of molecule arising from hyper-conjugative interactions and charge delocalization were analyzed using natural bond orbital (NBO) analysis. The electron density (ED) in the σ(*) and π(*) anti-bonding orbital and second order delocalization energies confirmed the occurrence of intermolecular charge transfer. The energetic behavior of the title compounds in solvent phase is examined using the B3LYP/6-311G(d,p) method by applying the Onsager and polarizable continuum model. The molecular electrostatic potential (MEP) surface was generated over the optimized geometry of the molecule to obtain the chemical reactivity of the molecule. The charge distribution of the mesogen molecules has been calculated. The reliability of the methods used has been assessed by comparing the theoretical results obtained from the experimental findings. Moreover, the mesomorphic behavior and the nematic phase stabilities for each molecule have been predicted using calculated local charge distribution. The simulated FT-IR spectrum of 5OBASA was agreed with experimentally observed spectrum.

Two series of supramolecular hydrogen-bonded liquid crystalline complexes have been designed and synthesized. A successful attempt has been made to form hydrogen bond between Suberic acid (SA) and Pimelic acid (PA) with p-n-alkyloxy benzoic acids (nBAO) by varying the respective alkyloxy carbon number. The first homologous series comprises of Suberic acid and p-n-alkyloxy benzoic acids (SA+nBAO), while the another series is formed between Pimelic acid and p-n-alkyloxy benzoic acids (PA+nBAO), where n represents the alkyloxy carbon number which varies from 5 to 12. These two homologous series are analyzed by polarizing optical microscope, differential scanning calorimetry, Fourier transform infrared spectroscopy (FTIR), and proton NMR studies. The formation of intermolecular hydrogen bond is evinced through FTIR and 1H-NMR. An interesting feature of PA+nBAO homologues series is the inducement of tilted smectic C phase with increasing carbon chain length. In the SA+nBAO homologues series oddeven effect is observed at isotropic to nematic transition temperatures. Phase diagrams of the above complexes are constructed and compared.