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Adsorption of Pb(II) using novel Pleurotus sajor-caju and sunflower hybrid biosorbent

100%

Majeed A. , Jilani M. I. , Nadeem R. , Hanif M. A. , Ansari T. M.

tom Vol. 40, nr 2

5--15

The present study was focused on the technical feasibility of using immobilized hybrid biomass of Pleurotos sajor-caju and sunflower for Pb(II) removal from the contaminated water. After preliminary evaluation, it was found that immobilized hybrid biomass of Pleurotos sajor-caju and sun-flower effectively removed Pb(II) from wastewater at pH 4.5. The effect of various experimental parameters on Pb(II) uptake by hybrid biosorbent was systematically evaluated in a batch biosorption system. The optimized biosorbent dose, contact time, initial metal concentration and temperature were 0.05 g/100 cm 3, 180 min, 800 mg/dm3 and 60 °C. Dynamics of the adsorption process were studied, and the values of rate constants of pseudo first order and pseudo second order kinetic models were calculated. Equilibrium isotherms for the adsorption of Pb(II) were analyzed by the Langmuir and Freundlich isotherm models. The sorption of Pb(II) followed the pseudo second order kinetic model. The Langmuir sorption isotherm fitted well to Pb(II) concentration data. The results revealed that this new hybrid biosorbent system was a promising candidate for eliminating Pb(II) from contaminated aquatic environment.

Allelopathic management of some noxious weeds by the aqueous extracts of Parthenium hysterophorus and Carthamus oxyacantha

100%

Siyar S. , Majeed A. , Muhammad Z. , Ullah R. , ul Islam S.

nr 2

Weed occurrence in cultivated fields may cause significant losses of agricultural crops as a result of competition and allelopathic stress. In this study, 100 g l-1 aqueous extracts of leaves and roots of two wild plants Parthenium hysterophorus and Carthamus oxyacantha were evaluated for their effect on germination, seedling growth and biomass of commonly occurring weeds in wheat fields (Chenopodium album, Lepidium didymium, Phalaris canariensis and Rumex dentatus). Negative allelopathic effect of P. hysterophorus and C. oxyacantha were observed on test weeds, however, 100 g l-1 leaf and root extracts of P. hysterophorus had a more drastic effect on the weeds than C. oxyacantha. The sensitivity of subject weeds to allelopathic stress were recorded in the order Lepidium didymium > Rumex dentatus > Chenopodium album> Phalaris canariensis. The study suggests that P. hysterophorus possesses phytotoxic activities and may serve as a potential candidate in natural weed management strategies

Występowanie chwastów na polach uprawnych może powodować znaczne straty plonów ro-ślin uprawnych w wyniku konkurencji i stresu allelopatycznego. W badaniu oceniano wpływ wodnych ekstraktów z liści i korzeni w stężeniu 100 g l-1 dwóch dziko rosnących roślin Parthe-nium hysterophorus i Carthamus oxyacantha na kiełkowanie, wzrost siewek i biomasę powszech-nie występujących chwastów na polach pszenicy (Chenopodium album, Lepidium didymium, Phalaris canariensis i Rumex dentatus). P. hysterophorus i C. oxyacantha oddziaływały allelopatycz-nie negatywnie na testowane chwaty. Przy czym ekstrakty w stężeniu 100 g l-1 z liści i z korzeni P. hysterophorus wykazywały silniejszy negatywny wpływ na chwasty niż z C. oxyacantha. Wrażli-wość chwastów na stres allelopatyczny wyglądała następująco: Lepidium didymum> Rumex denta-tus> Chenopodium album> Phalaris canariensis. Z badań wynika, że P. hysterophorus ma działa-nie fitotoksyczne i może być używany w strategiach zwalczania chwastów metodami naturalnymi

Influence of preparation method on structural, optical and magnetic properties of nickel ferrite nanoparticles

86%

Khan A. A. , Javed M. , Khan R. A. , Iqbal Y. , Majeed A. , Hussain S. Z. , Durrani S. K.

tom Vol. 35, No. 1

58--65

Nanocrystalline NiFe2O4 particles were prepared by conventional sol-gel, citrate-nitrate sol-gel combustion and co-precipitation methods. The synthesized samples were annealed at 1000 ºC for two hours and structural, chemical, morphological, optical and magnetic properties of nickel ferrite were investigated. The structural properties were investigated by X-ray diffraction (XRD) technique which confirmed the formation of single phase NiFe2O4 particles derived by the three methods. The chemical properties were analyzed by Fourier transform infrared (FT-IR) spectroscopy which confirmed the corresponding vibration modes in the samples. The optical properties were studied by UV-Vis spectroscopy. The morphological study of the as-synthesized samples was carried out by scanning electron microscopy (SEM). SEM images showed the agglomerated nanoparticles of NiFe2O4. The magnetic properties were investigated by vibrating sample magnetometer (VSM), which showed that the calcined samples exhibited typical magnetic behavior.