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The main purpose of this paper is to investigate the adsorption properties of CoFe_1.9Mo_0.1O₄ magnetic nanoparticles (CFMo MNPs) using, anionic dye “congo red (CR)” as a model of water pollutants.

The magnetic nano-adsorbent was synthesized via sol-gel process. Different techniques including; Fourier transform infrared spectroscopy, point of zero charge, scanning electron microscope and X-ray powder diffraction were used to characterize the prepared adsorbent. Adsorption experiments were conducted in batch mode under various conditions (contact time, shaking speed, initial dye concentration, initial solution pH, solution temperature and adsorbent amount) to investigate the adsorption capability of CFMo MNPs for CR.

The results showed that, CFMo MNPs could successfully remove more than 90% of CR dye within 20 min. Adsorption kinetics and isotherms were better described using pseudo-second-order (PSO) and Langmuir models, respectively. The maximum adsorbed amount (q_max) of CR dye was 135.14 mg/g. The adsorption process was found to be endothermic and spontaneous in nature as demonstrated by the thermodynamics ( ΔGo, ΔHoand ΔSo).

This study provided a good example of using an easily separated magnetic nano-adsorbent for fast removal of a very toxic organic pollutant, congo red, from the aquatic environment

The employment of Mo-doped cobalt ferrite for the first time for removing hazardous anionic dyes such as congo red from their aqueous solutions.

The purpose of this study was to prepare carboxylated attapulgite (APT-COOH) and then be used as one of the ligands to prepare metal organic framework (MOF) hybrid materials to reduce the cost of MOF materials and improve the dispersed condition of APT. And then the materials were used to enrich anionic dye Congo red from aqueous solution.

The MOF hybrid materials were designed by means of facile reflux method rather than hydrothermal method, characterized by Thermogravimetric Analysis (TGA), Fourier Transform Infrared (FTIR) Spectrometer and pore structure. The dispersed degree of APT-COOH in the MOF materials was validated according to adsorption efficiency for Congo red.

Due to introduction of APT-COOH, the microenvironment of the MOF materials changed, leading to different adsorption behaviors. Compared to the MOF material without APT-COOH, the adsorption capacities of the hybridized MOF materials with different amounts of APT-COOH introduced increased by 4.58% and 15.55%, respectively, as the initial concentration of Congo red solution of 300 mg/L. Meantime, hybridized MOF materials were suitable to remove Congo red with low concentration, while the MOF material without APT-COOH was appropriate to enrich Congo red with high concentration.

The microstructure of MOF hybrid materials in detail is the further and future investigation.

This study will provide a method to reduce the cost of MOF materials and a theoretical support to treat anionic dyes from aqueous solution.

APT-COOH was prepared and used as one of the ligands to synthesize MOF material to improve the dispersed degree of APT-COOH and reduce the cost of the MOF materials. The adsorption efficiency was greatly enhanced with low concentration of Congo red solution, and the results indicated that hydrogen bonding, electrostatic interaction, and p-p conjugation were involved in the adsorption process. The prepared MOFs materials exhibited excellent adsorption efficiency, which made the present materials highly promising and potentially useful in practical application as adsorbents to enrich anionic dyes such as Congo red from aqueous solution.

The purpose of this paper is to focus on the removal of Congo red dye from aqueous solution using magnetically separable novel adsorbent prepared by coating activated charcoal on magnetic nanoparticles.

The synthesized magnetic nanocomposite of activated charcoal was characterized using Fourier transform infra-red (FTIR), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis. The removal of Congo red from aqueous solution using magnetic nanocomposite of activated charcoal was optimized. The equilibrium and kinetics modeling of adsorption of Congo red was analyzed.

The presence of activated charcoal on magnetic nanocomposite was confirmed by FTIR analysis. The average size of the nanocomposite was found to be 12.77 nm using SEM characterization. The elemental composition by EDS analysis confirmed the increase in concentration of carbon due the adsorption of Congo red dye. The optimum conditions for batch adsorption was found to be 1 g/L of adsorbent, dye concentration 50 mg/L, pH 3 and temperature 70°C. The adsorption of Congo red dye on magnetic nanocomposite of activated charcoal was found to follow Temkin adsorption isotherm.

The experimental data were found to fit well with the pseudo second-order kinetics and the rate of adsorption was found to be controlled by intra-particle diffusion.

To treat water pollution, especially the contamination resulted from organic dyes has aroused significant attention around the world, this study aims to prepare the metal organic framework (MOF) materials hybridizing with poly(p-phenylene terephthalamide) (PPTA) by means of a facile refluxing method and to systematically investigate adsorption performance for anionic dye Congo red as target molecule from aqueous solution.

The MOF materials hybridized by PPTA were fabricated by virtue of a facile refluxing method, characterized by thermogravimetric analysis, X-ray powder diffraction, Fourier transform infrared and pore structure.

The results showed that pseudo-second-order kinetic model could better describe the adsorption process for all the four materials, whereas Elovich model also fitted the process for the hybrid materials with PPTA. Adsorption isotherm analyses indicated that Langmuir isotherm could be used to describe the adsorption process. Introduction of appropriate amount of PPTA could enhance the adsorption affinity of the MOF materials for Congo red, and the maximum adsorption capacity could reach as high as 1,053.41 mg/g while that of the MOF material without PPTA was 666.67 mg/g, indicating introduction of PPTA could change the microenvironment of the MOF materials and increase the adsorption sites, leading to high adsorption efficiency.

The microstructure of MOF hybridized materials in detail is the further and future investigation.

This study will provide a method to prepare MOF materials with high efficiency to treat anionic dyes like Congo red from aqueous solution.

Owing to the special characteristics of PPTA and similar to carbon tube, PPTA was introduced into MOF material to increased corresponding water stability. Because of aromatic ring and amide group on the surface of PPTA, the adsorption efficiency of the hybridized MOF material with appropriate amount of PPTA was greatly enhanced.

More than 25 years, researchers have observed that an insufficient understanding and mastering of related concepts to leadership and lifelong learning has not much contributed to the much-desired development in higher education. This chapter discusses the way in which past reforms of higher education in Democratic Republic of Congo have been conducted, and how its development was jeopardized by deep misunderstanding of the concept and principles of leadership and lifelong learning. Preliminary findings from the analysis of the experience of reforms in higher education may suggest strategies that could successfully apply to any future reforms of the higher education system in Democratic Republic of Congo. Leaders could also learn from a lifelong learning process that ought to exercise a strong political will and courage to shift from the model inherited from a colonial system.

Les différents stades de l'évolution des territoires d'Afrique peuvent se synthétiser de la façon suivante: