| Water is a major source for survival on this planet. Its conservation is therefore a priority. With the increase in demand, the supply needs to meet specific standards. Several purification techniques have been adopted to meet the standards. Many scientists and technicians focus on magnetic separation technology because of a rapid and effective technology for separating magnetic materials. Magnetic separation technology combined with adsorption process of adsorbent has been widely used in environmental purification applications. In addition, its combination with other processes enables an improvised efficient purification technology. Core-shell magnetic nano-sized ZnLa0.02Fe1.9804/PPy and ZnLao.o2Fe1.9804/SiO2were prepared in the present study. Effects of expermental conditions on adsorption of methyl orange(MO), methyl blue(MB), Cr (VI) were investigated. The experimental results demonstrate that these magnetic materials show higher adsorption capacities and separation convenience, and they can be used many times after desorption.Adsorption of MO by ZnLa0.02Fe1.98O4/PPyEffects of experimental conditions, such as pH, concentration of MO, contact time, and experimental temperature, on the adsorption of MO on ZnLa0.02Fe1.98O4/PPy were studied. The pH value of the solution affected significantly on the adsorption amount of the MO onto the adsorbent. The amounts decreased gradually with pH increasing from2.0to7.0, and then decreased drastically with increasing pH values from7.0to14.0. The adsorption efficiency and capacity are98%and19.6mg/g for10mg/L of MO solution, respectively, and74%and74.3mg/g for50mg/L of MO solution, at298K and pH=7.0. Langmuir adsorption model and pseudo-second-order model can be applied to describe the adsorption of MO on the as-prepared ZnLao.02Fe1.98O4/PPy.ΔGθ<0and AΔHθ<0indicate that the process of adsorption of MO on the ZnLao.02Fe1.98O4/PPy is a spontaneous and exothermic process.Adsorption of Cr(VI) by ZnLao.o2Fe1.9804/PPyEffects of experimental conditions, such as pH, concentration of Cr (ⅥⅥ)(K2Cr2O7), contact time, and experimental temperature, on the adsorption of Cr (VI) on ZnLa0.02Fe1.98O4/PPy were studied. The pH value of the solution affected significantly on the adsorption amount of the MO onto the adsorbent. The amounts decreased gradually with pH increasing from2.0to4.0, and then decreased drastically with increasing pH values from4.0to14.0. The adsorption efficiency and capacity are83%and17.7mg/g for10mg/L of K2Cr2O7solution, respectively, and60%and108.8mg/g for90mg/L of K2Cr2O7solution, at298K and pH=7.0. Langmuir adsorption model and pseudo-second-order model can be applied to describe the adsorption of MO on the as-prepared ZnLao.02Fe1.9gO4/PPy. ΔGθ<0and ΔHθ <0indicate that the process of adsorption of K2CrO7on the ZnLa0.02Fe1.98O4/PPy is a spontaneous and exothermic process.Adsorption of MB by ZnLa0.02Fe1.98O4/SiO2Magnetic ZnLa0.02Fe1.9804/SiO2was fabricated in the present study, in which effect of amount of H2O on the shell was investigated. The maximum thickness of the shell (about30nm) was obtained when10mL of H2O was added into the reaction system. And this sample shows highest adsorption efficiency of MB among the as-prepared magnetic ZnLa0.02Fe1.98O4/SiO2. So the ZnLao.02Fe1.9gO4/SiO2prepared with l0mL of H2O was selected for adsorption of MB with30,50,70and90mg/L of solutions, respectively. The adsorption efficiency are about100%for30and50mg/L of MB solutions, and about73%for90mg/L of MB solution. Langmuir adsorption model and pseudo-second-order model can be applied to describe the adsorption of MB on the as-prepared ZnLa0.02Fe1.98O4/SiO2.ΔGθ<0and ΔHθ<0indicate that the process of adsorption of MB on the ZnLa0.02Fe1.98O4/SiO2is a spontaneous and exothermic process. |
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