One of the most crucial attributes of synthetic organic chemistry is to design organic reactions under the facets of green chemistry for the sustainable production of chemicals.

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A one-pot method was employed to immobilize sulfonic acid onto silica obtained from rice husk ash using 3-(mercaptopropyl)trimethoxysilane to form a solid catalyst denoted as RHASO3H. BET measurements of the catalyst showed the surface area to be 340 m2 g−1 with the average pore volume of 0.24 mL g−1 and the pore diameter of 2.9 nm. Acidity test of cation exchange capacity and pyridine adsorption studies revealed the presence of Brønsted acid sites on the catalyst surface. The catalyst was used in the acetalization reaction of glycerol with benzaldehyde. Under optimized conditions, the reaction showed the maximum conversion of 78 % after 8 h with 67 % selectivity towards the five membered ring isomer. Variation in the glycerol concentration had a significant effect on the reactants conversion. A single crystal X-ray study of one of the products proved the existence of a unique trimer formed by hydrogen bonding by the six-membered cis-isomer. The catalyst was several times recycled without any loss of its catalytic activity.

This study was carried out to evaluate the efficiency of metals (Ni, Cr, and Mn) removal using, raw and carbonized rice, millet and corn husks as low cost adsorbents. The sorption of these metal ions from aqueous solution was determined using Atomic Absorption Spectroscopy Analysis (AAS). Characterisation of the adsorbents using Fourier Transform Infra Red) FTIR) and Scan Electron Microscopy (SEM) images revealed some changes before and after the adsorption process. This indicated that, most likely adsorption has been taken place between the metal ions and the adsorbents in the aqueous solution. Batch experiments were carried out to determine the effect of different parameters such as adsorbent dose, pH of the medium, contact time and agitation rate. The result obtained showed that the sorption process was largely dependent on metal ion concentration, adsorbent dose and contact time. The experimental data was analyzed using paired sample -T test. The study also showed that, all the husks were effective for the quantitative removal of various toxic heavy metals and can be used as low cost and highly efficient adsorbents for the removal of heavy metal ions from industrial effluents.Citation: Batagarawa SM, Ajibola AK. Comparative evaluation for the adsorption of toxic heavy metals on to millet, corn and rice husks as adsorbents.

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ABSTRACT:Widespread and growing use of medicinal plants has created public health challenges in terms of quality, safety and effectiveness. Using Atomic Absorption Spectrophotometer (AAS), concentrations of Ni, Zn, Mn, Cu, Cr and Pb, , were determined in samples of neem tree (Azadirachta indica) leaves obtained from Katsina, Dutsinma, Kankara and Funtua along Katsina -Dutsinma -Funtua highway in Katsina state of Nigeria. The mean level of the metals in the various locations along the highway varied between Ni (1.14mg/Kg and 1.92mg/Kg); Zn (2.48mg/Kg and 6.08mg/Kg);Mn (2.67mg/Kg and 4.72mg/Kg); Cu (1.91mg/Kg and 2.99mg/Kg); Cr (0.17mg/Kg and 0.37mg/Kg) and Pb (0.77mg/Kg and 2.25mg/Kg). Samples from Katsina indicated the highest levels of Zn, Ni and Pb while samples from Funtua indicated the highest levels of Cu and Cr. However, the levels of all metals obtained from the samples from various locations along the highway were below the WHO/FDA permissible levels of heavy metals in herbal plants. @JASEM

ABSTRACT:The levels of some heavy metals were determined in Funaria hygrometrica (moss plant) harvested from the streets of Dutsinma town of Katsina State of Nigeria using atomic absorption spectrometry. Over the years the town has witnessed influx of people from neighbouring villages, as a Local government headquarters. The mean level of the metals in the study area varied between Cd (0. -1 and 7.94µgg -1 ). The result shows relatively high levels for Cu, Fe, Mn, Pb and Zn in the plant. This was attributed to the concentrations of motor vehicles and some industries that have increased in the town over time. Other heavy metals (Cd and Ni) were found in relatively smaller concentrations. The absorption of these metals was related to their concentrations in the atmosphere as a result of industrial and automobile emissions. @ JASEM

This study shows that corn stalk (CS) is an effective adsorbent for malachite green (MG) and Congo red (CR) dyes. MG and CR sorption behavior onto the corn stalk adsorbent was investigated in this study. Basic condition w adsorbent. The pseudo second order equation well described MG and CR adsorption onto the CS adsorbent, hence chemisorptions was the main rate limiting step. The Freundlich Isotherm could describe the sorption data for the dyes. confirmed by FTIR and SEM study, as it showed the change in characterization before and after adsorption, Present investigation and comparison with other reported adsorbents concluded that, CS may be applied as a low from aqueous solution.