Adsorption of Dye by Waste Black Tea Powder: Parameters, Kinetic, Equilibrium, and Thermodynamic Studies

Abstract

Waste black tea powder was used as a potential adsorbent to remove methylene blue (MB) from aqueous solution. Several operating factors in adsorption of MB onto waste black tea powder were investigated, including contact time, initial MB concentration, solution pH, adsorption temperature, and dosage of waste black tea powder. Experimental results revealed that the adsorption efficiency increased with contact time and solution pH values and decreased with initial MB concentration and adsorption temperature. The equilibrium time was estimated to be around 60 min. The maximum adsorption capacity and the highest adsorption efficiency were 302.63 mg·g−1 and 100%, respectively. In kinetic study, pseudo-first-order and pseudo-second-order kinetic models, intraparticle diffusion model, and Boyd and Elovich models were employed to analyze the adsorption behavior and the adsorption mechanism. It was found that the pseudo-second-order kinetic model was suitable to describe the adsorption process, and the calculated equilibrium adsorption capacity was well close to the experimental data for different initial MB concentrations. The internal diffusion was not the only rate-controlling step, and the existence of boundary effect was observed in this study. From isotherm analysis, the equilibrium data were well represented by the Langmuir model, rather than Freundlich, Dubinin–Redushckevich, or Temkin models. The nonlinear fitting for various isotherm models implied that the adsorption behavior between MB and waste black tea powder was complication. Thermodynamic parameters including changes in Gibb’s free energy, enthalpy, and entropy suggested that adsorption of MB onto waste black tea powder was a spontaneous and exothermic process. The multiple regeneration/adsorption experiments indicated that the used black tea powder efficiently remained more than 75% after five cycles using NaOH as a regenerative reagent and thus be used for many times. Therefore, as a low-cost and easily available material, waste black tea powder could be applied in wastewater treatment.

One-pot synthesis of zinc oxide nanoparticles via chemical precipitation for bromophenol blue adsorption and the antifungal activity against filamentous fungi

“…This trend is consistent with the findings of other researchers 26 , 69 , 70 . Thus as the BRB concentration in the aqueous phase increased, more BRB molecules were fixed on the active sites of ZnONPs 71 , which resulted in site saturation, surface repulsions, and less percentage removal of dye from solution 72 . The BRB concentration of 50 mg/L was selected for the batch experiments due to the associated optimum adsorption capacity, which indicated effective utilization of the actives sites of the as-prepared ZnONPs.…”

Evaluation of Methylene Blue Sorption onto Low-Cost Biosorbents: Equilibrium, Kinetics, and Thermodynamics

“…Among these, adsorption is a very effective and attractive technique with respect to cost, ease of use, and simplicity [1][2][3]. Several studies have reported the use of low-cost materials for dye removal [15,16]. Various biosorbents such as Carica papaya [17], lotus leaf [18], olive stone [19], spent rice biomass [20], maize husk leaf [21], palm oil agrowaste [22], and pulverized marula seed husk [1] have been studied for sorption of methylene blue.…”

Fabrication of a novel biopolymer‐based nanocomposite (nanoTiO2‐chitosan‐plum kernel shell) and adsorption of cationic dyes

“…The pseudo-secondorder model explains the relationship between biosorbent and dyes through the sharing mechanism of the force of values or electrons, and assumes that chemisorption is the adsorption process and the rate-limiting step for the resulting reaction. 42 In order to study the behaviour of MB and MG adsorption kinetics for the nTiO 2 -Composite, pseudo-first-order and pseudo-second-order models were applied to kinetic studies (Fig. 8).…”