Adsorptive removal of lead from aqueous solutions by amine–functionalized magMCM-41 as a low–cost nanocomposite prepared from rice husk: Modeling and optimization by response surface methodology

In this study, the Pb(II) ions adsorption unto nanoscale zerovalent iron particles (nZVI) supported on rice husk has been carried out. The challenge of nanoparticles agglomeration makes immobilising them on rice husk desirable. Optimization of process parameters, pH (4 – 10), adsorbent dose (0.5 – 2.0 g) and contact time (60 – 300 min), was carried out using response surface methodology (RSM) based on Box-Behnken design. Optimum condition for maximum Pb(II) ions of 98.74% was predicted at contact time of 60.12 min, pH of 4.01 and adsorbent dose of 0.5 g. At these optimized conditions, 97.23% removal was achieved experimentally. Analysis of variance carried out on the experimental data showed that the model was significant with a R2 of 0.9883. The synthesised adsorbent was characterized with Fourier transform-infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The SEM showed that RH-nZVI has a very porous surface structure. Amine, carboxyl and hydroxyl groups were some of the identified functional groups present in the adsorbent for adsorption. This study suggests that nZVI supported on rice husk is a viable low-cost adsorbent for removing Pb(II) ions from wastewater.

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Kinetic, isotherm and thermodynamic aspects of Cu2+ biosorption onto Rosa damascena leaf as a low-cost biosorbent: Optimization of process variables by Response Surface Methodology

10.21203/rs.3.rs-1120602/v1 ◽

2021 ◽

Author(s):

Mustafa A. Fawzy ◽

Hatim M. Al-Yasi ◽

Tarek M. Galal ◽

Reham Z. Hamza ◽

Esmat F. Ali ◽

...

Keyword(s):

Response Surface Methodology ◽

Aqueous Solutions ◽

Response Surface ◽

Structural Characteristics ◽

Low Cost ◽

High Surface ◽

Isotherm Models ◽

Rosa Damascena ◽

Before And After ◽

Leaf Powder

Abstract In this study, the Rosa damascena leaf powder was evaluated as a biosorbent for copper removal from aqueous solutions. Optimized conditions of 4.0 g/L biosorbent dosage, pH of 5.5 and initial copper concentration of 55 mg/L obtained by Response Surface Methodology were employed for Cu2+ biosorption by R. damascena leaves and up to 88.7 % Cu2+ was removed. The biosorption data were well ﬁtted to the pseudo-second order and Elovich kinetic models. The Langmuir and Dubinin-Radushkevich isotherm models were also best fit the experimental data showing monolayer isotherm with qmax value of 25.13 mg/g obtained at optimum conditions. Thermodynamic parameters showed the spontaneity, feasibility and exothermic nature of adsorption. Scanning electron microscopy, Energy-Dispersive X-Ray, and Fourier transform infrared spectroscopy were used to characterize the biosorbent before and after Cu2+ biosorption, revealing outstanding structural characteristics and high surface functional groups availability. In addition, immobilized R. damascena leaves adsorbed 90.7 % of copper from aqueous solution, which is greater than free biosorbent (85.3 %). It can be concluded that R. damascena might be employed as a low-cost biosorbent for removing heavy metals from aqueous solutions.

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