Isotherm and kinetic studies on adsorption of malachite green using chemically synthesized silver nanoparticles

Choe

Environmental Engineering Research

et al. 2021

Because disinfectants have been essential during the COVID-19 pandemic, the global demand for benzalkonium chlorides (BACs) has significantly increased. BACs can inactivate coronaviruses, but are known as toxic. In this study, we investigated the adsorption mechanisms of BAC12, BAC14, and BAC16 in water using powdered activated carbon (PAC). The effects of the reaction time, pH, and temperature on the adsorption kinetics of BACs were examined. The adsorption reaction followed pseudo-second-order kinetics, and better fitted to the Langmuir isotherm than the Freundlich isotherm. The best adsorption of BACs was achieved at neutral pH conditions. Thermodynamic analysis revealed that adsorption of BACs onto PAC is a spontaneous and endothermic process. Competitive adsorption experiments revealed that BACs with longer alkyl chains were adsorbed more effectively onto PAC than shorter alkyl chain BACs, implying that, while the electrostatic interaction is an important adsorption mechanism for BAC12, van der Waals interaction plays a more important role during the adsorption of BAC14 and BAC16. Finally, we observed the partial detoxification (69%) BAC in adsorption treated water with PAC using a Microtox test.

Section: Adsorption Kineticsmentioning

confidence: 99%

Adsorption of benzalkonium chlorides onto powdered activated carbon: mechanisms and detoxification

Choe

Environmental Engineering Research

et al. 2021

“…There are few publications on the use of silver nanoparticle alone as adsorbent for MG and other dyes from water [12][13][14][15][16]. Although found to be efficient, none of the report has provided insight on the adsorptive removal of MG using silver nanoparticle (AgNPs) synthesized from Vigna unguiculata L. The readily available stem of Vigna unguiculata L. could possibly be utilized as low cost material for synthesis of AgNPs for MG removal.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of silver nanoparticle from Vigna unguiculata stem as adsorbent for malachite green in a batch system

et al. 2019

This study describes a simple and cost effective method for the synthesis of silver nanoparticles from locally available Vigna unguiculata L. stem extract, as alternative method to the expensive and toxic chemicals used, and its application as adsorbent for malachite green (MG) in a Batch system. The AgNPs were synthesized using AgNO 3 as precursor and stem extract as reducing and capping agent. The AgNPs were characterized using UV-Vis, SEM-EDX, FTIR and XRD. The effects of contact time, pH of solution, initial dye concentration, adsorbent concentration and temperature were studied and they proved useful in the description of the adsorption process. AgNPs showed SPR bands at 455 nm. The XRD micrographs showed face centered cubic crystal structure with average crystalline size of the synthesized nanoparticle of ~ 25 nm. Alkaloids present in Vigna unguiculata L. stem played a role in the reduction of AgNO 3. An optimum pH of adsorption was achieved at 9.0. The adsorption process was observed to be exothermic. Equilibrium isotherm models showed Langmuir isotherm with R 2 of 0.99194 and residual sum of squares (RSS) of 5.23541 × 10 −5 , indicating monolayer adsorption. Kinetic studies revealed Pseudo-first order kinetics best fitted the rate of adsorption and intra-particle diffusion revealed that the adsorption process was controlled by surface phenomenon and intra-particle diffusion. The results showed the applicability of AgNPs in adsorption. However, the relatively low percentage removal (21.6% at 200 ppm) suggests that Silver nanoparticle synthesized from Vigna unguiculata L. stem, alone may not be sufficient in the complete adsorption of MG dye.

Nanotechnol. Environ. Eng.

“…Their water adsorbing ability is due to the hydrophilic groups present in their structure. The organic pollutants get adsorb into hydrogels as the ionic groups of organic pollutants form physical or chemical interaction with hydrophilic groups of hydrogels [5][6][7][8][9][10]. The addition of reinforcing agents and using crosslinkers during their synthesis helps in increasing the mechanical strength of the hydrogels.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of a nanocomposite hydrogel for combined photocatalytic degradation of a mixture of malachite green and fast green dye

Sharma

ALOthman

Kumar

et al. 2017

In this study, starch/poly(alginic acid-cl-acrylamide)/Fe/Zn nanocomposite hydrogel (ST/PL(AA-clAAm)/Fe/Zn NCHG) was synthesized by polymerization/ co-precipitation method. This nanocomposite hydrogel was prepared with the notion to remove the mixture of organic pollutants from the water system. Mixture of malachite green and fast green dye was used to check the photocatalytic degradation ability of the prepared nanocomposite hydrogel. ST/PL(AA-cl-AAm)/Fe/Zn NCHG was characterized by X-ray diffraction, transmission electron microscopy, scanning electron microscopy and Fourier transform infrared. The degradation of the two dyes followed the pseudo-first-order kinetics. The results showed that by using the prepared nanocomposite hydrogel, 91% of malachite green and 82% of fast green dye, respectively, were degraded within 5 h of their contact.