This work reports the application of a straw ash from barley as a novel bioadsorbent for the removal of several heavy metals: Ni(II), Cd(II), Cu(II), and Co(II). Equilibrium and kinetic models for heavy metals sorption were developed by considering the effect of the contact time, initial heavy metal ion concentrations, effect of temperature, and initial pH. The adsorption of heavy metal ions have been studied in terms of pseudo-first- and -second-order kinetics, and the Freundlich, Langmuir and Langmuir–Freundlich isotherms models have also been used to the equilibrium adsorption data. The equilibrium data fitted well with the Langmuir–Freundlich model and showed the following affinity order of the material: Ni(II)>Cu(II)>Co(II)>Cd(II). The adsorption kinetics followed the mechanism of the pseudo-second-order equation for all systems studied, confirming chemical sorption as the rate-limiting step of adsorption mechanisms. The thermodynamic parameters (ΔG°, ΔH° and ΔS°) indicated that the adsorption of heavy metals ions were feasible, spontaneous and endothermic at 15–80°C
15 September 2010 in Journal of Environmental Science and Technology
Meat and some meat products are highly perishable due to their high-water content, pH, and high content of nutrients. Therefore, spoilage control in these products is one of the critical challenges in the food industry. On the other hand, the increasing widespread awareness about the undesirable effects of synthetic preservatives has promoted the breakthrough of the use of natural compounds or bio-preservation technology. Bio-preservation implies the application of microorganisms or their metabolites to extend the shelf life of food products. In this regard, according to the ancient and safe use of fermentation by lactic acid bacteria (LAB), their application in the bio-preservation of meat and meat products is gaining more attention. Thus, more understanding of the potential of LAB and their metabolites in the control of pathogens in meat and meat products can create new horizons in the production of safe and functional products with long shelf life. So, this article aims to review the recent knowledge about the bio-preservation of meat and meat products by LAB and their metabolites. Also, their antibacterial mechanism and potential for use in hurdle technology are discussed. The outcome of this review literature shows the high potential of various LAB strains and their metabolites especially bacteriocins as bio-preservatives in meat and meat products for extending their shelf life. In this regard, their combined use with other novel technologies or natural antibacterial compounds as hurdle technology is a more effective method that can compete with synthetic preservatives.
1 February 2019 in Journal of Environmental Chemical Engineering