Mohammad Ajmal

ADSORPTION STUDIES ON RICE HUSK: REMOVAL AND RECOVERY OF CD (II) FROM WASTEWATER

Adsorption behaviour of Ni(II), Zn(II), Cd(II) and Cr(VI) on untreated and phosphate-treated rice husk (PRH) showed that adsorption of Ni(II) and Cd(II) was greater when PRH was used as an adsorbent. Sorption of Cd(II) was dependent on contact time, concentration, temperature, adsorbent doses and pH of the solution. The Langmuir constants and thermodynamic parameters have been calculated at different temperatures. It was found that recovery of Cd(II) from synthetic wastewater by column operation was better than a batch process.

Studies on removal and recovery of Cr(VI) from electroplating wastes

Phosphate treated sawdust shows remarkable increase in sorption capacity of Cr(VI) as compared to untreated sawdust. The adsorption process is pH dependent. 100% adsorption of Cr(VI) was observed in the pH range <2 for the initial Cr(VI) concentration of 8–50 mg 1−1. The effect of various adsorbent doses at pH 2 confirms Langmuir adsorption isotherms. 100% removal of Cr(VI) from synthetic waste as well as from electroplating waste containing 50 mg 1−1 Cr(VI) was achieved by batch as well as by column processes. The adsorbed Cr(VI) on phosphate treated sawdust was recovered (87%) using 0.01 M sodium hydroxide.

Removal and recovery of heavy metals from electroplating wastewater by using Kyanite as an adsorbent

Kyanite, a commercial mineral has been utilized as an adsorbent for the removal of heavy metals, such as Ni(II), Zn(II), Cr(VI) and Cu(II) from electroplating wastewater. The effect of contact time, pH, concentration, adsorbent doses, particle size of the adsorbent, salinity and hardness, both in natural and wastewater on the adsorption of Cu(II) have been studied in detail. The adsorption of metal ions seems to be an ion exchange process. The adsorbed metals ions from electroplating wastewater were recovered by batch as well as column operation using dilute HCl solution. The column operation was found to be more effective compared to batch process.

Biophysical Insight into Furosemide Binding to Human Serum Albumin: A Study To Unveil Its Impaired Albumin Binding in Uremia

Exogenous substances like drugs, when absorbed, enter into the circulatory system and bind reversibly and extensively to human serum albumin (HSA). But transport of various drugs like a diuretic, furosemide (FUR), via albumin in uremia is seriously compromised due to accumulation of uremic toxins. The reason behind it is explored by investigating the binding mechanism of FUR to HSA. Isothermal titration calorimetry results show that FUR binds with HSA at high (Kb ∼ 10(4)) and low affinity (Kb ∼ 10(3)) sites whereas spectroscopic results predict binding at a single site (Kb ∼ 10(5)). Thermodynamic analysis shows that the HSA-FUR complex formation occurs via hydrogen bonds and hydrophobic interactions and undergoes slight structural changes, as evident by FTIR and far-UV CD. Further, the lifetime of HSA decreases only marginally and thus the magnitude of energy transfer efficiency is small, as obtained by time-resolved measurements. A displacement experiment predicts that the FUR binds mainly to site I but a new site having lower affinity is also observed, which shares some residues with site II as supported by molecular docking results. Results revealed that in uremia, FUR indirectly competes for Arg410, Lys414, and Ser489 with site II bound uremic toxins and directly competes for site I with site I bound uremic toxins.

A Comprehensive Insight into Binding of Hippuric Acid to Human Serum Albumin: A Study to Uncover Its Impaired Elimination through Hemodialysis

Binding of hippuric acid (HA), a uremic toxin, with human serum albumin (HSA) has been examined by isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC), molecular docking, circular dichroism (CD) and fluorescence spectroscopy to understand the reason that govern its impaired elimination through hemodialysis. ITC results shows that the HA binds with HSA at high (K b ∼104) and low affinity (K b ∼103) sites whereas spectroscopic results predict binding at a single site (K b∼103). The HA form complex with HSA that involves electrostatic, hydrogen and hydrophobic binding forces as illustrated by calculated thermodynamic parameters. Molecular docking and displacement studies collectively revealed that HA bound to both site I and site II; however, relatively strongly to the later. Esterase-like activity of HSA confirms the involvement of Arg410 and Tyr411 of Sudlow site II in binding of HA. CD results show slight conformational changes occurs in the protein upon ligation that may be responsible for the discrepancy in van’t Hoff and calorimetric enthalpy change. Furthermore, an increase in and is observed from DSC results that indicate increase in stability of HSA upon binding to HA. The combined results provide that HA binds to HSA and thus its elimination is hindered.

Acute toxicity of chrome electroplating wastes to microorganisms: adsorption of chromate and chromium(VI) on a mixture of clay and sand

Chrome electroplating wastes were collected from two industrial sites and analyzed for color, turbidity, pH, alkalinity, sulfate, chloride, N-ammonia, N-nitrate, N-nitrite, acid hydrolyzable P, dissolved oxygen, biochemical oxygen demand, chemical oxygen demand, chromate and chromium(VI). The effect of these wastes on saprophytic and nitrifying bacteria was studied with varying concentrations of the waste using sucrose substrate as a source of C chain for microorganisms. The use of clay sand mixtures as adsorbents for chromate and chromium(VI) was investigated. Mixtures high in clay content were found to be suitable media for the removal of Cr from the wastes. The clay used was characterized by determination of the following parameters: pH, electrical conductivity, water soluble salts, osmotic pressure, cation exchange capacity, CaCO3 and organic matter.

Macrocyclic Compounds as Corrosion Inhibitors

Abstract The influence of three macrocyclic compounds on corrosion of mild steel (MS) in hydrochloric acid (HCl) was investigated using weight loss, potentiodynamic polarization, alternating current (AC) impedance, and hydrogen permeation techniques. All the investigated compounds showed significant efficiencies and reduced permeation of hydrogen through MS in HCl. Inhibition efficiency (IE) varied with the nature and concentrations of the inhibitors, temperature, and concentrations of the acid solutions. The addition of iodide ions (I−) increased IE of all the tested compounds as a result of the synergistic effect. Potentiodynamic polarization results revealed that macrocyclic compounds acted as mixed inhibitors in 1 M HCl to 5 M HCl. Adsorption on the metal surface obeyed Temkins adsorption isotherm. Auger electron spectroscopy (AES) of the polished MS surface, exposed with tetraphenyldithia-octaazacyclotetradeca-hexaene (PTAT) proved adsorption of this compound on the surface through nitrogen and sulf...

Interaction of new kinase inhibitors cabozantinib and tofacitinib with human serum alpha-1 acid glycoprotein. A comprehensive spectroscopic and molecular Docking approach

In the current study we have investigated the interaction of newly approved kinase inhibitors namely Cabozantinib (CBZ) and Tofacitinib (TFB) with human Alpha-1 acid glycoprotein (AAG) under simulated physiological conditions using fluorescence quenching measurements, circular dichroism, dynamic light scattering and molecular docking methods. CBZ and TFB binds to AAG with significant affinity and the calculated binding constant for the drugs lie in the order of 10(4). With the increase in temperature the binding constant values decreased for both CBZ and TFB. The fluorescence resonance energy transfer (FRET) from AAG to CBZ and TFB suggested the fluorescence intensity of AAG was quenched by the two studied drugs via the formation of a non-fluorescent complex in the static manner. The molecular distance r value calculated from FRET is around 2 nm for both drugs, fluorescence spectroscopy data was employed for the study of thermodynamic parameters, standard Gibbs free energy change at 300 K was calculated as -5.234 kcal mol(-1) for CBZ-AAG interaction and -6.237 kcal mol(-1) for TFB-AAG interaction, standard enthalpy change and standard entropy change for CBZ-AAG interaction are -9.553 kcal mol(-1) and -14.618 cal mol(-1) K(-1) respectively while for AAG-TFB interaction, standard enthalpy and standard entropy change was calculated as 4.019 kcal mol(-1) and 7.206 cal mol(-1) K(-1) respectively. Protein binding of the two drugs caused the tertiary structure alterations. Dynamic light scattering measurements demonstrated the reduction in the hydrodynamic radii of the protein. Furthermore molecular docking results suggested the Hydrophobic interaction and hydrogen bonding were the interactive forces in the binding process of CBZ to AAG while in case of TFB only hydrophobic interactions were found to be involved, overlap of the binding site for two studied drugs on the AAG molecule was revealed by docking results.

Insight into the interaction of antitubercular and anticancer compound clofazimine with human serum albumin: spectroscopy and molecular modelling

The binding of clofazimine to human serum albumin (HSA) was investigated by applying optical spectroscopy and molecular docking methods. Fluorescence quenching data revealed that clofazimine binds to protein with binding constant in the order of 104 M−1, and with the increase in temperature, Stern–Volmer quenching constants gradually decreased indicating quenching mode to be static. The UV–visible spectra showed increase in absorbance upon interaction of HSA with clofazimine which further reveals formation of the drug–albumin complex. Thermodynamic parameters obtained from fluorescence data indicate that the process is exothermic and spontaneous. Forster distance (Ro) obtained from fluorescence resonance energy transfer is found to be 2.05 nm. Clofazimine impelled rise in α-helical structure in HSA as observed from far-UV CD spectra while there are minor alterations in tertiary structure of the protein. Clofazimine interacts strongly with HSA inducing secondary structure in the protein and slight alterations in protein topology as suggested by dynamic light scattering results. Moreover, docking results indicate that clofazimine binds to hydrophobic pocket near to the drug site II in HSA. Graphical abstract

Effects of a textile factory effluent on soil and crop plants

Abstract The effluent of the Modi Textile Factory Ltd, Modinagar, UP(MTF) was analysed and its effects in various concentrations (25, 50, 75 and 100%) on certain physicochemical properties of soil and germination and growth of kidney bean Phaseolus aureus and ladys finger Abelmoschus esculentus crops were studied. The effluent was found to be rich in various types of soilds, BOD, COD, Cl−, SO42−, Na+, K+, Ca2+ and Mg2+, deficient in dissolved oxygen and highly alkaline in nature. At all the dilutions tested there was an increase in the water-soluble salts, electrical conductivity, cation-exchange capacity, pH, NH3-N, phosphorus, organic matter and NH4O Ac-extractable Na+, K+, Ca2+ and Mg2+ of the soil. The greatest changes were recorded with 100% effluent, the most marked increase being in the organic matter of soil, followed by NH3-N, K+, Na+, P, Ca2+ and Mg2+. The other effluent concentrations also changed soil composition accordingly. The top soil supplemented with different dilutions of the effluent had higher concentrations of water-soluble salts and extractable nutrients than the subsoils. The soils supporting crops were found to have lower concentrations of nutrients than those without crops. The plants grown in different effluent concentrations were analysed for Na+, K+, Ca2+ and Mg2+. Na+ showed a constant and gradual increase with increase in the effluent concentration, whereas K+, Ca2+ and Mg2+ concentrations were found to be highest in the plants grown in 50% effluent followed by 25, 75 and 100% effluent. Germination was inhibited and delayed by 100 and 75% effluent, whereas it was normal with other effluent concentrations as compared to water control. Undiluted and 75% effluent retarded the growth of plants whereas 50% effluent enhanced the growth.