In this study, the adsorption of Pb2+ and Zn2+ ions from aqueous solutions onto lignin obtained from unmodified Sarkanda grass was analyzed. To ensure optimal process conditions, the retention of lead and zinc ions was tested at different experimental parameters (pH of the initial solution and adsorbent, the dose of adsorbent, the concentration of aqueous solutions and contact time). The experimental results have been interpreted using the classic Langmuir and Freundlich isotherm models, as well as two kinetic models (the Lagergren pseudo-first order and the Ho and McKay pseudo-second order models). Based on the analysis of the experimental data, it has been concluded that unmodified Sarkanda grass lignin can be recommended as an efficient alternative, considering its practical applicability, in the retention of Pb2+and Zn2+ ions from aqueous solutions, both in terms of the amount of adsorbate and pollutant species retained, as well as in terms of adsorption time.
"Considering the negative effects of polluting species on the environment and human health, in particular heavy metals, and the need for efficient use of resources, the present study investigated the adsorption of As (III) from aqueous solutions under static conditions onto chemically unmodified Sarkanda grass lignin. In order to optimize the adsorption process, the retention of As (III) was tested under various experimental parameters (pH of the initial solution and adsorbent, concentration of aqueous solutions, adsorbent dose and contact time of the two phases). The experimental data obtained were interpreted based on the classical models of Freundlich and Langmuir isotherms, which was useful in establishing the equilibrium conditions and in evaluating the adsorption capacity for a solute. The adsorption dynamics was studied using the Lagergren pseudo-first order and the Ho and McKay pseudo-second order models. The analysis of the obtained experimental data recommends chemically unmodified Sarkanda grass lignin as a future alternative adsorbent for water remediation, taking into account its practical applicability in the retention of As (III) from aqueous solutions, in terms of both adsorbent and adsorbed doses, as well as the time required for adsorption. "
Polymers are of great interest in areas such as agriculture, medicine and pharmacy, the food and cosmetic industries, and the chemical and construction industries. However, many polymers are nonbiodegradable and are not environmentally friendly. They are highly resistant to degradation and therefore can lead to waste disposal problems. In recent years, the interest in the microbial degradation of polymeric materials has grown due to the desire for less waste pollution in the environment. In this study, the biodegradable polymer that was obtained by the ring-opening polymerization of ε-caprolactone (CL) using an aminopropyl-polydimethylsiloxane (APDMS) oligomer and the effects of the polymer towards the growth and development of tomato plants (Lypercosium esculentum) were investigated. The obtained product was characterized using FTIR spectroscopy, NMR spectroscopy, and energy dispersion spectroscopy (EDX) analysis, and the effects of this compound on the evolution of tomato plants (Lypercosium esculentum) were studied. We also studied the biological stability of the product by identifying some of the microorganisms that developed on the surface, given its susceptibility to biodegradation.
In the present work, the possibility of increasing the calcium carbonate (CaCO3) content in sheets of paper to optimize their properties was investigated. A new class of polymeric additives for papermaking is proposed as well as a method for their use in paper sheet containing the CaCO3 precipitated addition. Calcium carbonate precipitated (PCC) and fibers cellulose were adjusted with a cationic polyacrylamide flocculating agent (polydiallyldimethylammonium chloride (plyDADMAC) or cationic polyacrylamide (cPAM)). PCC was obtained in the laboratory by a double-exchange reaction between calcium chloride (CaCl2) and sodium carbonate (Na2CO3) suspension. After testing, the dosage of PCC was established at 35%. To improve the systems of additives studied, the materials obtained were characterized and their optical and mechanical properties were analysed. The PCC had a positive influence over all of the paper samples, but in the case of use of cPAM and polyDADMAC polymers the paper obtained had superior properties compared to the paper obtained without additives. Also, the samples obtained in the presence of cationic polyacrylamide exhibit superior properties to those obtained in the presence of polyDADMAC.
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