Motrescu Iuliana

Cornhusk Powders as Adsorbents for Nitrites in Solution: A Thermodynamic and Kinetic Approach

Alina Elena Trofin, Elena Ungureanu, Iuliana Motrescu, Lucia Carmen Trincă, Denis Constantin Țopa, Diana Beatrice Eperjessy

ABSTRACT. The retention of nitrite ions in solutions of different concentrations by three cornhusks-based powders was analyzed. Natural cornhusk powder (NCHP), as waste obtained from local market, the alkalized cornhusk powder (ACHP) and the biochar from the original material (CHBC) have been characterized through scanning electron microscopy (SEM) and elemental composition EDAX – TEAM analysis (Energy dispersive analysis X-ray – Texture and ele-mental analytical microscopy) and tested for the removal of nitrite ions. The influence of initial nitrite concentration and contact time was studied under slow stirring rate conditions (150 rpm). For all three adsorbents both Freundlich and Langmuir isotherm equations described the process with R2 > 0.95, denoting physical adsorption and chemisorption on the surface. The estimated retained quantities (mg·g-1) determined from isotherms were 4.4783 (NCHP), 8.3542 (ACHP) and 8.7413 (CHBC). The Ho&McKay model was better adjusted to the adsorption data with R2 > 0.985, while the Lagergren model produced regression factors between 0.61 and 0.88. Considering the biggest concentration of nitrite solution of 50 mg·L-1 and the longest contact time of 150 minutes, the equilibrium capacity qe (mg·g-1) predicted by the Ho&McKay model for the considered adsorbents were: 4.5065 (NCHP), 8.5179 (ACHP) and 8.9445 (CHBC) compared to the obtained qt (mg·g-1) of 4.4384 (NCHP), 8.0685 (ACHP) and 8.5753 (CHBC). The nitrite uptake in the experiments reached a maximum of 2.2192 mg·g-1 on NCHP, 4.0342 mg·g-1 on ACHP and 4.2877 mg·g-1 on CHBC. Considering the cost-effective treatment steps, there is the possibility of valorising an important amount of waste as adsorbent materials.

Keywords: cornhusks powder; nitrite removal; waste valorisation.

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Comparative Analysis of The Influence of Different Biostimulators on the Germination and Sprouting Behaviour of Four Wheat Varieties

Alina Elena Marta, Cristina Slabu, Mihaela Covașă, Iuliana Motrescu, Carmenica Doina Jităreanu

ABSTRACT. Wheat is an important cereal around the world and is a nutrient source in people’s diets. In this work, we focused on the potential of some biostimulators on four wheat varieties – Dropia, Glosa, Gruia, and Pegasus, with a focus on the effects during the first developing stages from germination to the appearance of the second leaf. Our results indicated that germination and some biochemical traits can be strongly influenced by biostimulants, with the effects also depending on the genetic background of the variety. Some treatments proved beneficial for germination, and also growth as found by the biometric measurements, while others inhibited both traits. Some of the biostimulants increased the concentration of the photosynthetic compounds, thus being recommended for use during all stages of wheat development. Dropia, Glosa, and Gruia reacted positively in most tests, their germination and plant and root development were stimulated by Super fifty, Atonik, Asfac, and Cropmax. Thus, we recommend the use of these biostimulants in the first development stages. The concentrations of photosynthetic pigments increased after treatment with Asfac, Atonik, and Cropmax. The treatment showing the most inhibitory effects was Lebosol.

Keywords: wheat; biostimulator; wheat sprouts.

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