Asian Journal of Applied Chemistry Research

Increased anthropogenic activities have led to serious environmental problems due to pollution caused by toxic materials such as heavy metals whose levels are rising in the environment. The inefficiency and high cost of conventional methods of waste treatment have prompted the investigation of environmentally friendly and cheaper methods of treatment using natural products. In this study, G. arborea leaves powder was investigated with a view of using it as cheap material for the biosorption of Pb²⁺ and Cd²⁺   from wastewater. The effects of operational parameters like pH, biosorbent dose [g/L], initial metal ions concentration [mg/L], contact time [minutes] and stirring speed [rpm] on the biosorption efficiency [%] were determined. The optimum solution pH for Pb²⁺ and Cd²⁺adsorption was 5.0 and peak adsorption of 91.33% and 82.53% for Pb²⁺ and Cd^2+, respectively. 5 g/L Melina leaves were enough to achieve peak removal of both metal ions. The removal of the metal ions was comparatively quick, and stability was achieved after 30 minutes. The optimum stirring speed was 250 rpm for both metal ions. The uptake efficiency of the biosorbent was determined by Langmuir and Freundlich isotherm models. The value of Langmuir isotherm separation parameter [RL] of Pb²⁺ ion [0.0446 - 0.78125] and Cd²⁺ [0.1005- 0.9482] were within range of 0 -1 indicating favorable biosorption for both metal ions. The degree of non-linearity [n] values between Pb²⁺ [12.79] and Cd²⁺ [11.79] solution concentration and biosorption in Freundlich equation were greater than 1, indicating physical biosorption of Pb²⁺ and Cd²⁺ on to G. arborea leaves. G. arborea can serve as efficient biosorbent not only for Pb²⁺ and Cd²⁺ ions but also for other heavy metal ions in a wastewater stream

Aims: The study aims: (I) To synthesise N-(4-(tert-butyl) benzyl)-1-(4-tert-butyl) phenyl)-N-methyl methanaminium chloride, an  analogue  of butenafine from tertiary-butyl benzyl derivatives, (II) to compare the solvent actions of Tetrahydrofuran (THF), acetonitrile, methanol and 1,2-dichloroethane (DCE), and the reducing efficiencies of NaBH₄ and sodium triacetoxyborohydride (STAB) during the synthesis.

Study Design:  The study involved laboratory experiments leading to the synthesis of the target compound by varying the non-aqueous solvents used, the reducing agent and the temperature of the operations. Silica chloride catalyst was used to speed up the reaction in one of the syntheses and in each synthesis, Thin Layer Chromatography was used to monitor the progress of the reaction. The time taken by each reaction and the yield were used as the basis for determining the solvent action and the reducing efficiency. 

Place and Duration of Study: M.Sc. Access controlled Teaching Laboratory, School of Chemistry, Newcastle University, New castle upon Tyne, United Kingdom from June to August 2012.

Methodology: Reductive amination was carried out by reacting 4-tert-butylbenzaldehyde and 4-tert-butylbenzylamine, using the direct and then the indirect approaches. This was followed by methylation using the Eschweiler-Clarke reaction in each of the two approaches. The time taken by each reaction was monitored and the product of each approach was characterised by EIS-MS, ¹H NMR, ¹³C NMR and FTIR.

Results: 1,2-dichloroethane gave the best solvent action at 40°C (Yield: 75%) and NaBH₄  gave the best-reducing action with silica chloride catalyst at 25°C (Yield: 50%). At the end of each synthesis,  in all obtained  products, ¹H NMR spectrum gave a single peak of 18 hydrogen atoms at 1.3 -1.5 ppm for the existence of 6 methyl groups in the two tertiary-butyl substituents, the ¹³C NMR spectrum also showed a peak at  31-32 ppm for the six methyl carbon atoms in the two tertiary-butyl substituents, the FTIR spectrum showed  a strong band at  2460 cm^-1 for the presence of a tertiary ammonium ion and finally the EIS-MS gave  a mass to charge ratio of 324.2693 as a confirmation of the relative molecular mass of the compound.

Conclusion:  The target compound can be synthesised by both direct and the indirect approaches of reductive amination in any of the solvents tested with/without a catalyst at room or elevated temperature using NaBH₄ or STAB as a reducing agent but the best solvent action can be achieved with DCE at 40°C and the best-reducing action can be achieved with NaBH₄ in the presence of silica chloride.

This study provides an insight into a province of Santa Fe region of a developing country, namely San Cristobal and Huanqueros, Argentina and a possible link between arsenic, copper and iron concentration in toenail, fingernail and hair in the population. A multivariate statistical tool, known as Principal Component Analysis (PCA) was applied to explain the behaviour of the elements in toenails, fingernails, drinking waters and hair using multi- base 2013 excel add- ins. Correlation test, error bars, and a 2-factor ANOVA test were employed. Results from one hundred and twenty- nine (n=129) samples of tap well water (n=23), rainwater (n=20), bottled water (n=6) and treated well water (n=80) and each of toenail, fingernail and hair (n=129) samples from the subjects were determined and the results compared with the previous works. Mean, standard deviation, covariance and maximum and minimum for each variable were reported. The hypothesis is to understand if there is a correlation between fingernail and toenail metals levels and make a comparison with previous researches. Results show that a positive correlation exists between fingernail and toenail metals concentrations. Also, the study reveals higher concentrations of arsenic, copper and iron in the samples tissues compared with the values available in the previous works. The elevated levels of these metals may be attributed to the drinking water sources. Since this study highlighted elevated levels of these metals, consumptions of contaminated drinking water should be constantly monitored. Finally, the application of multivariate statistical techniques can provide powerful information on heavy metals bioaccumulation analysis in human and environment.

The study was undertaken to evaluate groundwater quality both for drinking and irrigation usage collected from the Sadar upazila of Jamalpur district, Bangladesh. Total 20 groundwater samples were collected from the whole area and analysed for various physicochemical parameters following standard protocols at the Department of Agricultural Chemistry, Bangladesh Agricultural University, Mymensingh during March to December 2017. Concentrations of different heavy metal (Fe, Mn, Cu, Pb, Cr, Cd and Zn) in groundwater samples were measured by an atomic absorption spectrophotometer (AAS). Major cation chemistry showed their dominance in order of Ca > Mg > Na > K. Among the anions, HCO₃ was the most dominating ion, which makes all groundwater unsuitable for irrigation. But considering major cations and anions, all groundwater samples were rated as suitable for drinking. In context of heavy metals, the amounts of Mn, Cd and Pb in groundwater were comparatively higher than the standard limits, which makes 14, 8 and 19 samples problematic for irrigation, and 13, 18 and 1 samples unsuitable for drinking, respectively. Electrical conductivity (EC) and sodium adsorption ratio (SAR) reflected that all groundwater samples were low to medium salinity (C1-C2) and low alkalinity (S1) hazards classes. As regards to hardness, out of 20 groundwater samples, 9 samples were classified as moderately hard, 10 were hard and only 1 sample was very hard in quality. According to residual sodium carbonate (RSC), 18 groundwater samples were found in suitable class, 1 sample was rated as marginal and the rest 1 was categorised as unsuitable class. The study concluded that HCO₃, Mn, Cd and Pb were the major contaminants in groundwater of Sadar upazila of Jamalpur district, Bangladesh. Finally, the study suggested that the groundwater in this area needs to treat to minimise the amount of contaminants before using both for irrigation and drinking.

Present work was aimed at studying the variation of non polar metabolites content in Gossypium hirsutum L. under water stress condition using a gas chromatography-mass spectrometry (GC-MS) technique. A total of 17 non-polar metabolites were detected in control and water stressed G. hirsutum leaf. The major metabolites were quinoline derivative (26.37±0.29%), 2- methylhexadecan-1-ol (7.47±0.07%), phytol (7.71±0.02%), myristic acid (5.94±0.04%), hexadecanol (14.30±0.94%), nonadecane (1.67±0.05%) and palmitic acid (3.20±1.39%). Fourteen metabolites were detected in control and water stressed G. hirsutum stem. The major metabolites were dodecene (1.67±0.11%), L-lysine (0.65±0.06%), dibutylphthalate (5.06±1.88%), linoleic acid (10.26±0.07%), campesterol (0.87±0.04%) and stigmasterol (1.13±0.55%). Statistical analysis of GC-MS data was carried out by Mann-Whitney U test without normal distribution using statistical software SYSTAT version 12.0. Significant variation in the content of the most of the metabolites were observed between control and water stressed leaf or stem (Mann-Whitney U test, P =0.05). It concludes that the major metabolites played an important role during water stress and can be consider as metabolites responsible for water stress tolerance in G. hirsutum.