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Investigation of nickel adsorption onto low Jordanian zeolite dose: efficiency and Langmuir – Freundlich behaviour

Al-Ghazawi Ziad, Qasaimeh Ahmad, Al-Bataina Bilal

Journal of Water and Land Development

2021

no. 50

150--157

In this work, nickel adsorption onto low Jordanian zeolite dose is being investigated. Natural zeolite doses were stirred continuously with nickel solutions in batch reactors at 180 RPM for 24 hours, where the temperature was set to 20°C. The pH was initially 4.5 and reached 5.2 at equilibrium. The removal efficiency of nickel reaches maximum value when the initial nickel concentration is around 1 ppm and then tends to decrease when the initial nickel concentration increases above 1 ppm. The optimal nickel removal reaches 65% when the initial nickel concentration is 1 ppm and the zeolite dose is 26 mg∙dm–3. This study investigates the behaviour of nickel removal and modelling isotherms below and above this critical peak point. At this level of zeolite dose, the adsorption does not follow either Freundlich or Langmuir isotherms, but rather, it follows Freundlich for the data plot just below the peak point with the highest coefficient of determination (R2) equals (0.98) when the zeolite dose is (26 mg∙dm–3), whereas it follows Langmuir for the data plot just above the peak point with the highest coefficient of determination (R2) equals (0.99) when the zeolite dose is (10 mg∙dm–3). These findings clarify the theory behind each isotherm and can be used to find new information for efficient treatment techniques.

Search of radiation hormesis in plants : irradiation of the cress (Lepidium sativum L.)

Fornalski K. W., Adamowski Ł., Turowski T. W., Wojnarowicz J.

Nukleonika

2012

Vol. 57, No. 3

421-426

The paper is composed of two parts : a review of a group of experiments among irradiated plants and own search for radiation hormesis in a single experiment. In the first part the Bayesian analysis of the hormetic-like data published so far shows that the NOAEL (no observed adverse effect level) point, above which adverse effects appear, may be located between 30 and 100 Gy. In the second part the influence of low doses of ionizing radiation was tested on the particularly fast growing plant, namely the cress (Lepidium sativum L.). Two experimental scenarios were used : in the first one the cress was irradiated during the growth (maximal dose 2.3 Gy), while in the second scenario dry seeds were irradiated (maximal dose 100 Gy). The experiment indicates that the NOAEL point lies above 100 Gy and statistically insignificant hormetic effect can be seen between 0.1 and 14 Gy. No linear reaction is observed in the full range of doses.