2021 ◽  
Vol 2021 ◽  
pp. 1-16
Author(s):  
Adugna Nigatu Alene ◽  
Gietu Yirga Abate ◽  
Adere Tarekegne Habte ◽  
Desiew Mekuanint Getahun

The aim of this study was to investigate the adsorption characteristics of malachite green (MG) dye onto the raw (RLAPW) and activated (ALAPW) surface of Lupinus albus seed peel waste prepared via physicochemical activation under alkaline condition as a dye adsorbent. Proximate analysis, surface area (Sears’ method), point of zero charge (pHzpc), and FTIR analysis were used to characterize the adsorbents. The effects of operational parameters such as pH (4) for ALAPW and pH (6) for RLAPW, adsorbent dose (0.2 g), initial dye concentration (30 mg/L), contact time (60 min), and temperature (298 K) were optimized. The experimental data well fitted with the Freundlich adsorption isotherm with the adsorption capacity of 7.3 mg/g for activated Lupinus albus seed peel waste (ALAPW) and Sips isotherm for raw Lupinus albus seed peel waste (RLAPW) with the adsorption capacity of 6.6 mg/g. The kinetics data well fitted to pseudo-second-order kinetic model for both adsorbents. Thermodynamic study revealed that the bioadsorption process using bioadsorbents was spontaneous and exothermic in nature. Desorption experiment was conducted and showed desorption efficiency at an acidic pH of 2. The results showed that the prepared adsorbents exhibited good adsorption capacity and can be used as an alternative adsorbent for the adsorptive removal of malachite green dyes.


Author(s):  
Violeta Rakić ◽  
Milena Miljković ◽  
Vojkan Miljković ◽  
Marjan Ranđelović

The goal of this study was to investigate the possibility of using natural materials based on clay and polysaccharides of carboxymethylcellulose as adsorbents for removing the textile dye malachite green from its solution. In this article, adsorption of dye on native clay and modified clay containing 3% carboxymethylcellulose was compared. The experimental results of dye adsorption with native and modified clay were interpreted using theoretical models of adsorption isotherms. The best match of the experimental results for native clay was achieved with the Langmuir model, and a slightly lower degree of correlation existed for the Freundlich's model. A good matching with the Langmuir's model indicates monolayer dye adsorption as well as certain energy homogeneity of the surface. After modification of the clay with carboxymethylcellulose, a better maching with the Freundlich's model was observed. This indicated that, as a consequence of the application of carboxymethylcellulose, the surface of the clay was changed in chemical and energy terms. The native clay had a lower adsorption capacity compared to clay modified with carboxymethylcellulose. The use of modified clay to remove the dye of malachite green was advisable in very concentrated solutions, because it showed obvious advantages compared to native clay.


2017 ◽  
Vol 47 (2) ◽  
pp. 927 ◽  
Author(s):  
I.K. Georgiadis ◽  
A. Papadopoulos ◽  
A. Filippidis ◽  
A. Godelitsas ◽  
A. Tsirambides ◽  
...  

Raw bauxite from Klisoura mine (Prefecture of Fokida, Greece) containing 72 wt.% diaspore, 16 wt.% hematite, 6 wt.% quartz, 4 wt.% anatase and 2 wt.% calcite, has been used for the removal of malachite green dye from aqueous solutions. The batch type experiments were conducted with 10 ml of solution, at pH = pHZPC = 6.7 and contact time 1 h. The initial concentration of malachite green dye was 10 mg/l, the bauxite quantity was 0.02 g, 0.04 g, 0.06 g, 0.1 g and 0.2 g. The highest adsorption capacity achieved was 4.5 mg/g (90% removal) using 0.02 g bauxite. The removal capacity of raw bauxite is comparable to other non-conventional adsorbents, such as neem sawdust, sugar cane dust and cane root carbon.


2021 ◽  
Vol 18 (10) ◽  
Author(s):  
Aldes LESBANI ◽  
Tarmizi TAHER ◽  
Neza Rahayu PALAPA ◽  
Risfidian MOHADI ◽  
Mardiyanto Mardiyanto ◽  
...  

The ZnAl Layered double hydroxides (LDHs) have been successfully synthesized by the coprecipitation method, followed by intercalation using Keggin ion of α-dodecatungstosilicic acid [α-SiW12O40]4- to form ZnAl-[α-SiW12O40] LDHs. The prepared ZnAl-[SiW12O40] LDHs were characterized by using X-Ray, FTIR, and BET surface area analyses, which were, then, used as adsorbents of malachite green dye from aqueous solution. The synthesized ZnAl LDH showed a typical diffraction peak of the layered compound at 11o (003) with an interlayer space of 8.59 Å. After intercalation, it was recorded that the interlayer space of ZnAl-[SiW12O40] LDH increased to 10.65 Å. Moreover, the specific surface area of the intercalated LDH increased from 1.9685 to 14.0422 Å. The adsorption study revealed that the adsorption capacity of ZnAl-[SiW12O40] LDH toward malachite green dye was higher (37.514 mg.g-1) than the pristine ZnAl LDH (32.845 mg.g-1). The adsorption kinetics study showed that malachite green adsorption onto both pristine and intercalate LDH followed the pseudo-2nd-order model. The adsorption thermodynamic investigation indicated that adsorption of malachite green onto ZnAl-[SiW12O40] LDH was a spontaneous process and was classified as physical adsorption with activation energy ranging from 10.074 to 15.476 kJ.mol-1. HIGHLIGHTS ZnAl LDH intercalated by Keggin ion has been successfully synthesized by facile coprecipitation followed by ion exchange method The basal spacing of the intercalated ZnAl LDH increased up to 10.65 A The intercalated ZnAl LDH exhibited higher adsorption capacity for malachite green dye removal compared with the original ZnAl LDH


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