Study of the Adsorption of L-Phenylalanine, L-Tryptophan, and L-Tyrosine from Aqueous Samples by Fe3O4 Modified Magnetic Nanoparticles with Ionic Liquid

ما نانو ذراتي از نوع Fe3O4 تركيب دوتايي آن با مايع يوني 1-اكتيل -3-متيل ايميدازوليوم برميد را تهيه و شناسايي كرديم و در جذب آلانين، تريپتوفان و تيروزين مورد استفاده قرار گرفت. اندازه ذرات ميانگين و مورفولوژي سطح نانو ذرات با تكنيك هاي FTIR، XRD و TEM بررسي شد. pH نقطه بار صفر هردوي نانوذرات و نانوذرات تركيب شده با مايع يوني بدست آمد. نتايج آزمايشي تحت شرايط بهينه زير بدست آمد: مقدار نانوذره 015/0 گرم و زمان هاي پاسخ 5، 10 و 15 دقيقه به ترتيب براي تريپتوفان، تيروزين و فنيل آلانين در غلظت اوليه 4-10×0/5 مولار از آمينو اسيد. ارزيابي هاي ايزوترم نشان مي دهد مدل فروندليج نسبت به مدل دابينين-رادوشكويچ با داده هاي تجربي تطابق بيشتري دارد. ماكزيمم ظرفيت جذب براي تريپتوفان، تيروزين و فنيل آلانين عبارتست از: 740/12، 55/3 و 62/35 ميلي گرم بر گرم جاذب. فرآيند جذب گرماگير مي باشد. هر دو فنيل آلانين و تيروزين امكان واجذب شدنشان از جاذب به وسيله محلول هاي 0/1 و 0/2 مولار NaOH وجود دارد. همچنين تريپتوفان بطور كامل در حضور محلولي از NaCl 0/1 مولار و NaOH 0/1 مولار از جادب واجذب مي شود. بنابراين نانودرات قابليت دوباره استفاده شدن را دارند.

Fe3O4 nanoparticles and their binary mixtures ([C8MIM]-Fe3O4) with 1-Octyl-3-methylimidazolium bromide were prepared and characterized as ionic liquid for using in the adsorption of phenylalanine, tryptophan, and tyrosine. The characteristics of [C8MIM]-Fe3O4 nanoparticles were investigated via using TEM, XRD and FTIR techniques. The pH of the point of zero charge (pHpzc) of both Fe3O4 and [C8MIM]-Fe3O4 were obtained based on the experimental curves corresponding to the immersion technique. Experimental results were obtained under optimum operational conditions of: nanoparticle amount of 0.015 g and a contact times of 5, 10, 15 minutes for tryptophan (Trp), tyrosine (Tyr) and phenylalanine (Phe), respectively, when initial concentration of each amino acid was 5.0×10?4 mol L?1. The isotherm evaluations revealed that the Freundlich model attained better fits to the equilibrium data than the Dubinin-Radushkevich model. The maximum obtained adsorption capacities of Tyr, Trp and Phe were 12.74, 3.55 and 35.62 mg amino acid per gram of adsorbent, respectively. The applicability of pseudo-first order and pseudo-second order kinetic models was estimated on the basis of comparative analysis of the corresponding rate parameters, equilibrium adsorption capacity and correlation coefficients. Furthermore, the adsorption processes were found endothermic. Both phenylalanine and tyrosine were desorbed from [C8MIM]-Fe3O4 nanoparticles by using NaOH aqueous solution with concentrations of 1.0 and 2.0 mol L?1, respectively. Tryptophan was completely desorbed in the presence of a mixture of 1.0 mol L?1 NaCl and 1.0 mol L?1 NaOH. The nanoparticles thus were recycled.