Nisha K. Shah

Adsorptive removal of nickel(II) ions from aqueous environment: A review.

Among various methods adsorption can be efficiently employed for the treatment of heavy metal ions contaminated wastewater. In this context the authors reviewed variety of adsorbents used by various researchers for the removal of nickel(II) ions from aqueous environment. One of the objectives of this review article is to assemble the scattered available enlightenment on a wide range of potentially effective adsorbents for nickel(II) ions removal. This work critically assessed existing knowledge and research on the uptake of nickel by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites. The systems performance is evaluated with respect to the overall metal removal and the adsorption capacity. In addition, the equilibrium adsorption isotherms, kinetics and thermodynamics data as well as various optimal experimental conditions (solution pH, equilibrium contact time and dosage of adsorbent) of different adsorbents towards Ni(II) ions were also analyzed. It is evident from a literature survey of more than 190 published articles that agricultural solid waste materials, natural materials and biosorbents have demonstrated outstanding adsorption capabilities for Ni(II) ions.

Adsorptive amputation of hazardous azo dye Congo red from wastewater: a critical review.

AbstractIncreasing amount of dyes in an ecosystem has propelled the search of various methods for dye removal. Amongst all the methods, adsorption occupies a prominent place in dye removal. Keeping this in mind, many adsorbents used for the removal of hazardous anionic azo dye Congo red (CR) from aqueous medium were reviewed by the authors. The main objectives behind this review article are to assemble the information on scattered adsorbents and enlighten the wide range of potentially effective adsorbents for CR removal. Thus, CR sorption by various adsorbents such as activated carbon, non-conventional low-cost materials, nanomaterials, composites and nanocomposites are surveyed and critically reviewed as well as their sorption capacities are also compared. This review also explores the grey areas of the adsorption performance of various adsorbents with reference to the effects of pH, contact time, initial dye concentration and adsorbent dosage. The equilibrium adsorption isotherm, kinetic and thermodynamic data of different adsorbents used for CR removal were also analysed. It is evident from a literature survey of more than 290 published papers that nanoparticle and nanocomposite adsorbents have demonstrated outstanding adsorption capabilities for CR. Graphical abstractᅟ

Enhanced corrosion inhibitive effect of p-methoxybenzylidene-4,4′-dimorpholine assembled on nickel oxide nanoparticles for mild steel in acid medium

The corrosion inhibition efficiency of p-methoxybenzylidene-4,4′-dimorpholine (p-MBDM) and p-MBDM assembled on nickel oxide nanoparticles (NiONPs) was investigated using three techniques: weight loss, electrochemical impedance spectroscopy (EIS), and galvanostatic polarization. For the first time, p-MBDM and p-MBDM assembled on NiONPs were used as efficient inhibitors for mild steel (MS) in 2 M hydrochloric acid (HCl) solution. From weight loss measurements, the results show that the inhibition efficiency increases with an increase in inhibitor concentration. Moreover, with increasing temperature, the inhibition efficiency increases for p-MBDM assembled on NiONPs, whereas it decreases for p-MBDM only. EIS spectra demonstrate that the charge transfer resistance in the case of p-MBDM assembled on NiONPs is comparatively more than that of p-MBDM. Analysis of polarization data indicates that both inhibitors act as mixed type inhibitors. The present study reveals that p-MBDM assembled on NiONPs is more efficient than p-MBDM alone. Additionally, the characterization of synthesized products was performed by proton nuclear magnetic resonance (1H NMR), transmission electron microscopy (TEM), dynamic light scattering (DLS), Fourier transform infrared (FTIR) spectroscopy, powder X-ray diffraction (PXRD), and electrospray ionisation mass spectrometry (ESI-MS). The surface morphology of the MS was further carried out by scanning electron microscopy (SEM) and atomic force microscopy (AFM).

Synthesis and antimicrobial studies of s-triazine based heterocycles.

In an effort to discover new candidates with improved antimicrobial activities we report here the synthesis and in vitro biological evalution of various series of 2-(N-methylamino)-4-(N,N-dimethylamino)-6-(arylthioureido)-s-triazine (5a–j) and (N-methylamino)-4-(N,N-dimethylamino)-6-(arylureido)-s-triazine (6a–j). All the synthesized compounds were screened in vitro for their antibacterial activity against two different gram-positive bacteria (S. aureus, B. subtilis) and two different gram-negative bacteria (P. aeruginosa, E. coli) using the broth dilution method.

Comparative study of chitin and chitosan beads for the adsorption of hazardous anionic azo dye Congo Red from wastewater

AbstractChitin (CH) and chitosan (CTS) beads used and compared for the adsorption of Congo Red (CR), an anionic azo dye, are reported in the present work. Initially, the adsorbents were prepared and characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR) analysis. SEM images showed the heterogeneous and porous structure of the beads and FT-IR results confirm the presence of –OH, –NH2, and–NHCOCH3 groups which are responsible for the adsorption of CR. Further, batch studies were conducted to evaluate the adsorption capacity of CH and CTS beads and the effects of the parameters like pH, adsorbate concentration, contact time, and dosage of adsorbents on adsorption were investigated. From the analysis, it was observed that the amount of CR adsorbed on both the adsorbents increases with increasing initial dye concentration and decreasing pH. The adsorption isotherms were analyzed using the Langmuir and Freundlich isotherms. The Langmuir isotherm was the best-fit adsorption is...

Nanoparticles Loaded Biopolymer as Effective Adsorbent for Adsorptive Removal of Malachite Green from Aqueous Solution

In the present study, the biocompatible nanocomposite (nickel oxide nanoparticles loaded chitin beads (NiO NPs/CH)) was synthesized, characterized by using scanning electron microscopy (SEM) and Fourier transform infrared (FT–IR) analysis and then study its prospective application towards adsorption of malachite green (MG) dye. Further, batch studies were conducted to evaluate the adsorption capacity of nanocomposite, and the effects of various parameters, i.e., pH, adsorbate concentration, contact time, dosage of adsorbent and temperature, were investigated. The results revealed that the amount of MG adsorbed on the adsorbent increases with increasing initial dye concentration and by decreasing temperature. The equilibrium MG adsorption data on NiO NPs/CH were best described by the Langmuir isotherm model. Besides, the adsorption kinetics followed pseudo-second-order rate equation. Thermodynamic parameters such as free energy of adsorption (ΔG°), enthalpy (ΔH°), and entropy (ΔS°) changes were calculated, and the results suggested that the adsorption process was spontaneous and exothermic in nature. Based on the results, it was concluded that the nanocomposite can be sustainably prepared and efficiently used for the adsorptive removal of MG from colored aqueous solutions.

Malachite green “a cationic dye” and its removal from aqueous solution by adsorption

Adsorption can be efficiently employed for the removal of various toxic dyes from water and wastewater. In this article, the authors reviewed variety of adsorbents used by various researchers for the removal of malachite green (MG) dye from an aqueous environment. The main motto of this review article was to assemble the scattered available information of adsorbents used for the removal of MG to enlighten their wide potential. In addition to this, various optimal experimental conditions (solution pH, equilibrium contact time, amount of adsorbent and temperature) as well as adsorption isotherms, kinetics and thermodynamics data of different adsorbents towards MG were also analyzed and tabulated. Finally, it was concluded that the agricultural solid wastes and biosorbents such as biopolymers and biomass adsorbents have demonstrated outstanding adsorption capabilities for removal of MG dye.

Design, synthesis and antimicrobial study of some pyrimidine derivatives

A series of 4-[4-(2, 4-dichloro-5-fluorophenyl)-6-(4-methoxyphenyl)pyrimidine-2-yl]-1-(arylaminocarbonyl/thiocarbonyl)semicarbazides was synthesized and their in vitro antibacterial activity was studied.

Inhibitive effect of salicylidene‐N‐N′‐dimorpholine towards corrosion of zinc in hydrochloric acid

Purpose – The purpose of this paper is to describe the behavior of salicylidene‐N‐N′‐dimorpholine as a corrosion inhibitor for zinc in hydrochloric acid and the mechanism of its action.Design/methodology/approach – The effects of various parameters on the behavior of this inhibitor have been studied using weight loss, galvanostatic polarization, and cathodic protection methods. Thermodynamic parameters and adsorption data also were utilized.Findings – The inhibitor showed excellent corrosion inhibition (>99 percent) at effective concentration. It appeared from thermodynamic parameters that an efficient inhibitor is characterized by a relatively greater decrease (i.e. more negative) in free energy of adsorption (ΔGA°), positive values of entropy of adsorption (ΔSA°), and lower heat of adsorption (QA). Galvanostatic polarization data indicate that this is a “mixed” type inhibitor with predominant effect on the cathode. The inhibitor followed Langmuir adsorption isotherm behavior. The cathodic protection ind...

Adsorption of lead (II) ions onto novel cassava starch 5-choloromethyl-8-hydroxyquinoline polymer from an aqueous medium

Adsorption of lead (II) ions onto cassava starch 5-choloromethyl-8-hydroxyquinoline polymer (CSCMQ) was investigated with the variation in the parameters of pH, contact time, lead (II) ions concentration, temperature and the adsorbent dose. The Langmuir and Freundlich models have been applied. CSCMQ was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. Results showed that the adsorption process was better described by the Langmuir model. Adsorption kinetics data obtained for the metal ions sorption were investigated using pseudo-first-order, pseudo-second-order and intraparticle diffusion model. The maximum adsorption capacities (qm) were 46.512, 43.859 and 42.735 mg/g at 25, 35 and 45 °C, respectively. The dynamical data fit well with the second-order kinetics model. The results indicate that CSCMQ could be employed as low-cost material for the adsorption of Pb(II) ions from aqueous medium.