Adsorptive Removal of Malachite Green from Model Aqueous Solutions by Chemically Modified Waste Green Tea Biomass

Abstract

The adsorption of malachite green (MG) from aqueous solution by waste green tea (WGT) biomass was investigated. A series of experiments in batch conditions were conducted in order to assess the MG removal on WGT, following adsorbent quantity and temperature influences. Maximum removal efficiency for untreated WGT was 89% (4 g biomass, 100 mL solution of 94 mg/L, 316 K). It was found that the adsorption of MG increased by increasing temperature from 296 to 316 K. Thermodynamic parameters (ΔH°, ΔS°, ΔG°) were calculated, and indicated that dye adsorption onto the studied biomass was endothermic and non-spontaneous. Six chemical treatments were tested (four acidic -H 3 PO 4 , H 2 SO 4 , HCl, and tartaric acid, one oxidant -H 2 O 2 , and one basic -NaOH) in order to study the chemical groups responsible for MG adsorption onto WGT biomass. The alkali and acidic treatments led to an increase of adsorption efficiency up to 92% and 95% (H 2 SO 4 ) respectively. The FTIR spectroscopy results emphasized the modifications of the biomass surface and how these are influencing the adsorption process.

Dye Removal from Aqueous Solution using Low Cost Bioadsorbents Derived from Agricultural Waste: A Review

“…Batch mode studies for light green dye uptake from aqueous solutions by cationic surfactant hexadecylpyridinium bromide surfactant reveled that adsorption kinetics was well described by pseudo first order kinetic model and Elovich equation and equilibrium data well fitted to Langmuir adsorption isotherm. Calculations of thermodynamics parameters revealed spontaneity and exothermic nature of adsorption process and regeneration of exhausted modified peanut husk was done using 0.01 M NaOH solutions [37]. A commercial coffee waste modified using cationic surfactants cetyl trimethyl ammonium bromide (CTAB) / cetyl pyridinium chloride (CPC) was investigated for the capacity to adsorb methyl orange form aqueous solutions.…”

Green Tea Waste as an Efficient Adsorbent for Methylene Blue: Structuring of a Novel Adsorbent Using Full Factorial Design

“…To the best of our knowledge, all the reported efforts were based on the conventional univariate approach where each variable is treated as a separate entity and only one factor is varied at a time. Table 1 shows a summary of these approaches, including the reported percentage removal (%R) as well as the adsorption capacity (q e , mg/g) [20][21][22][23][24]. As the objective of the current investigation was to structure a green, cost-effective, and efficient adsorbent via recycling of waste materials, a two-level full factorial design (2 k -FFD) was executed.…”

A Comparative Study on the Adsorption of Two Remazol Dyes on Green Adsorbent

“…Adsorption as a water cleaning method has been found to be more favorable than other treatments due to its low cost, simplicity of design, ease of operation, and insensitivity of toxic substance [6]. Recently, many researchers have focused on finding low cost and available adsorbents from agricultural, industrial, household wastes: green tea [7], sandpaper waste [8], corn cob [9], sawdust [10][11][12], microcline particles [13], bentonite [14][15][16], agricultural waste [17][18][19], brown alga [20], soy bean and mustard husk [21], wheat bran [22], wood fiber [23]. Eggshell was also used as a possible adsorbent for cyanide, heavy metal, phenol, phosphate, pharmaceutical antibiotics and dye removal [24][25][26][27][28][29][30][31][31][32][33][34].…”