Numerical investigations of response surface methodology for organic dye adsorption onto Mg-Al LDH -GO Nano Hybrid: An optimization,kinetics and isothermal studies

We developed Mg-Al LDH intercalated with NO₃^- decorated Graphene Oxide nanohybrid with positive cationic textile dye adsorption, such as methylene blue. Contact time, initial dye concentration, and pH were among the independent variables used in the study. The Response Surface Model (RSM) was used to optimise and describe the interdependencies of the different variables. The method was evaluated using the Box-Behnken design (BBD). A second-order polynomial model was used to understand the experimental results, and the effectiveness of the chosen model was verified by its strong agreement in determination coefficient values. The adsorption results suited the best for the Langmuir isotherm than the D-R and Freundlich isotherms, resulting in efficient adsorption of 187.62 ?mg/g, proving LDH-GO is an effective dye adsorbent. Simultaneously, the kinetics were based on the pseudo-second-order model, and additional kinetic factors such as Elovich, pseudo-first-order, and intra-particular diffusion were examined. According to Thermodynamic studies, the adsorption process is spontaneous, which is exothermic and characterised by increased randomness. According to a regeneration test, even after four cycles, 37% of the removal efficiency for MB can be achieved. Based on this report, these materials can be used as an adsorbent to remove the dye.     

Microwave assisted solvent-free synthesis of N-phenyl-4-(pyridin-4-yl)thiazoles and their drug-likeness studies

A new, fast and solvent-free method is offers to synthesize thiazoles by condensation of 4-bromoacetylpyridine with substituted N-phenylthiourea under microwave irradiation. This approach delivers good to excellent yields of thiazoles within 5 min without using any catalyst and allows various functionalities. In comparison to the traditional heating approach, this method enables for the synthesis of different thiazole analogues with several advantages. In compliance with the Lipinski rule of five, the synthesized analogues demonstrated drug-like characteristics.     

Preparation and characterization of γ-In2Se3 thin-film photoanodes for photoelectrochemical water splitting

Journal of Solid State Electrochemistry - Indium selenide (γ-In2Se3) films were prepared using RF magnetron sputtering. Influence of deposition time on structural, optical, morphological, and...     

Design and synthesis of triazole-based peptide dendrimers

A series of novel designer dendrimers (8, 9, 11, 13 and 16) was synthesized by employing click chemistry. The dendritic structures reported here include symmetrical, unsymmetrical and cationic dendrimers with a variety of cores such as triazole, cystine and Lys-Asp dipeptide.     

Model for cage formation in colloidal suspension of laponite

In this paper we investigate glass transition in aqueous suspension of synthetic hectorite clay, laponite. We believe that upon dispersing laponite clay in water, the system comprises of clusters (agglomerates) of laponite dispersed in the same. Subsequent osmotic swelling of these clusters leads to an increase in their volume fraction. We propose that this phenomenon is responsible for slowing down of the overall dynamics of the system. As clusters fill up the space, the system undergoes glass transition. Along with the mode coupling theory, the proposed mechanism rightly captures various characteristic features of the system in the ergodic regime as it approaches glass transition.     

Poly(ethylene glycol) (PEG) as an efficient and recyclable reaction medium for the synthesis of dibenz[b,f]-1,4-oxazepine

Poly(ethylene glycol) (PEG) has been used as a sustainable, non-volatile, and environmentally friendly reaction solvent for the synthesis of dibenz[b,f]-1,4-oxazepine (2a). PEG-400 as a promoter provided 89% of 2a within 8 h. We compared the reactivity of PEG-400 with 18-crown-6, tetra-n-butylammonium bromide and ionic liquids as phase transfer catalysts. Further, we investigated our protocol with various PEGs, with molecular weight 200, 300, 1000, 2000, 8000, 10,000, and 20,000. The reaction provided excellent yields with low as well as high molecular weight PEGs. We also studied the effect of various organic cosolvents (polar protic/aprotic/non-polar) on the reactivity of PEG-400 for the synthesis of 2a.     

Bacteria-mediated precursor-dependent biosynthesis of superparamagnetic iron oxide and iron sulfide nanoparticles

The bacterium Actinobacter sp. has been shown to be capable of extracellularly synthesizing iron based magnetic nanoparticles, namely maghemite (gamma-Fe2O3) and greigite (Fe3S4) under ambient conditions depending on the nature of precursors used. More precisely, the bacterium synthesized maghemite when reacted with ferric chloride and iron sulfide when exposed to the aqueous solution of ferric chloride-ferrous sulfate. Challenging the bacterium with different metal ions resulted in induction of different proteins, which bring about the specific biochemical transformations in each case leading to the observed products. Maghemite and iron sulfide nanoparticles show superparamagnetic characteristics as expected. Compared to the earlier reports of magnetite and greigite synthesis by magnetotactic bacteria and iron reducing bacteria, which take place strictly under anaerobic conditions, the present procedure offers significant advancement since the reaction occurs under aerobic condition. Moreover, reaction end products can be tuned by the choice of precursors used.     

Green synthesis and dye-sensitized solar cell application of rutile and anatase TiO2 nanorods

Journal of Solid State Electrochemistry - Nanorods (NRs) of TiO2 have biogenically been prepared, i.e., from the extract of Phellinus linteus mushroom. The presence of mixed anatase and...     

Hydrophobization of Melamine Sponges Using Radiation-Synthesized Tetrafluoroethylene Telomers

High Energy Chemistry - The process of hydrophobization of melamine sponges has been investigated. Solutions of radiation-synthesized tetrafluoroethylene telomers, which had different chain lengths...     

Time–aging time–stress superposition in soft glass under tensile deformation field

We have studied the tensile deformation behaviour of thin films of aging aqueous suspension of Laponite, a model soft glassy material, when subjected to a creep flow field generated by a constant engineering normal stress. Aqueous suspension of Laponite demonstrates aging behaviour wherein it undergoes time-dependent enhancement of its elastic modulus as well as its characteristic relaxation time. However, under application of the normal stress, the rate of aging decreases and in the limit of high stress, the aging stops with the suspension now undergoing a plastic deformation. Overall, it is observed that the aging that occurs over short creep times at small normal stresses is the same as the aging that occurs over long creep times at large normal stresses. This observation allows us to suggest an aging time–process time–normal stress superposition principle, which can predict rheological behaviour at longer times by carrying out short time tests.