Arif Reza; Faheem A Sheikh; Hern kim; Mohammad Afzal Zargar; M. Zainal Abedin
Abstract
The present study deals with the study tea waste as an effective functional adsorbent for the removal of reactive blue 21(RB21) from aqueous solutions. The batch adsorption experiments were influenced by several parameters such as contact time, solution pH and mass of adsorbent and initial dye concentration. ...
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The present study deals with the study tea waste as an effective functional adsorbent for the removal of reactive blue 21(RB21) from aqueous solutions. The batch adsorption experiments were influenced by several parameters such as contact time, solution pH and mass of adsorbent and initial dye concentration. The results indicated that the maximum removal of RB21 dye by tea waste was after 90 minutes of contact time and at the nearly neutral pH of 6.0. Moreover, two isotherm models, namely Langmuir and Freundlich adsorption isotherm were used to describe the adsorption equilibrium of RB21 dye onto tea waste. The data obtained was in good agreement with Langmuir model than that of Freundlich model, showing a monolayer adsorption capacity of 28.99 mg/g. Furthermore, it was observed that tea waste did not require any supplementary pre-treatments; such as activation before the application. Collectively, this work highlights the promise of pristine TW, ability to harness it for adsorption of dyes, while also prioritizing areas for future research and development (e.g., collection of TW from local vendors and resulting in environmental friendly disposal of the same). The presented strategy exhibited excellent adsorption capacity of TW for the removal of RB21 from the aqueous solutions. Nonetheless, in most parts of the globe TW from local vendors is available without any cost, regeneration is not required and the saturated adsorbent can be disposed by incineration.
Aida Mohammadi; Abolghasem Ataie; Saeed Sheibani
Abstract
Barium hexaferrite (BaFe12O19) magnetic nano-powder was prepared by co-precipitation method. The effectiveness of different chemical synthesis variables such as solvent and mechanical milling on the adsorption efficiency of barium hexaferrite nano-particles to remove Cr (VI) ions from aqueous solutions ...
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Barium hexaferrite (BaFe12O19) magnetic nano-powder was prepared by co-precipitation method. The effectiveness of different chemical synthesis variables such as solvent and mechanical milling on the adsorption efficiency of barium hexaferrite nano-particles to remove Cr (VI) ions from aqueous solutions was examined. Structural, magnetic, and adsorption properties of the powders are investigated by different techniques. X-ray diffraction analysis revealed that barium hexaferrite formed at a relatively low temperature of 700?C in the sample prepared with a mixture of water/alcohol as a solvent. The FESEM and VSM studies confirmed that all samples had a plate like structure with a particle size in the range of 87-145 nm and high magnetic properties. It was demonstrated that nanometer barium hexaferrite was produced to be an operative adsorbent for removal of Cr (VI) ions from solutions. Different Cr (VI) adsorption experiments were carried out by controlling effective adsorption factors. It was revealed that the sample calcined at a temperature of 700°C and then milled for 5 h (owing themaximum surface area 13 m2/g) showed the highest removal efficiency of 99.5% at pH 3.0, amount of nano adsorbent 1.5 g, initial chromium concentration 133 mg/l, and contact time 1 h. FTIR analysis showed that due to the existence of Cr-O stretching band on the surface of nano-particles, the electrostatic reaction between Cr (VI) ions and nano-adsorbent is possible. The adsorption data were best fitted with the pseudo-second-order kinetic model. Also, the equilibrium adsorption capacity of Cr (VI) calculated from adsorption experiments was found to be 13.25 mg/g. Adsorption studies indicated that the potential use of barium hexaferrite nano-adsorbents for the removal of the other heavy metal ions without sacrificing adsorption capacity can be practical.
