Removal of Methylene Blue by Adsorption onto Retama Raetam Plant: Kinetics and Equilibrium Study

Abstract

Abstract. The feasibility of using medicinal plants species Retama raetam as a low cost and an eco-friendly adsorbent for the adsorption of cationic dye methylene blue from simulated aqueous solution has been investigated. Adsorption kinetics of methylene blue onto Retama raetam plants was studied in a batch system. The effects of pH and contact time were examined. The methylene blue maximum adsorption occurred at pH 8 and the lowest adsorption occurred at pH 2. The apparent equilibrium was reached after 120 min. Optimal experimental conditions were determined. Adsorption modelling parameters for Freundlich and Langmuir isotherms were determined and, based on R 2 , various error distribution functions were evaluated as well. Adsorption isotherm was best described by non linear Freundlich isotherm model. Thermodynamic studies show that adsorption was spontaneous and exothermic. For determining the best-fi t-kinetic adsorption model, the experimental data were analyzed by using pseudo-fi rst-order, pseudo-second-order, pseudo-third-order, Esquivel, and Elovich models. Linear regressive and non-linear regressive method was used to obtain the relative parameters. The statistical functions were estimated to fi nd the suitable method that fi t better the experimental data. Both methods were appropriate for obtaining the parameters. The linear pseudo-second-order (type 9 and type 10) models were the best to fi t the equilibrium data. The present work showed that plant Retama raetam can be used as a low cost adsorbent for the removal of methylene blue from water.Keywords: Retama raetam, methylene blue, removal, modelling, adsorption. IntroductionThe textile industry is one of industrial waste water source. This contaminated water is very toxic for the humans and animals [1]. Methylene blue is used in colouring paper, dyeing cottons, wools, silk, leather and coating for paper stock. Although methylene blue is not strongly hazardous, it can cause some harmful effects, such as heartbeat increase, vomiting, shock, cyanosis, jaundice, quadriplegia, and tissue necrosis in human organisms [2].Chemical coagulation-fl occulation [3], different types of oxidation processes [4], biological process [5], membrane-based separation processes [6] and adsorption [7] were the treatments used in the purifi cation of waters. The most effi cient method used for the quickly removal of dyes from the aqueous solution is the physical adsorption [8]. Biosorbents, such as wood sawdust [9], waste-biomass [10], delonix regia [11], agricultural solid waste [12], are able to remove effi ciently the colour from water.Retama raetam plants can be used as biosorbent. This species belonging to the Fabaceae family has a very productive vertical and horizontal root system, which can reach 20 m. This, in turn, increases substantially the stabilization of the soil. Moreover, the Retama species contributes to the biofertilisation of poor grounds, because of their aptitude to associate with fi xing nitrogen bacteria Rhizobia. Therefore, the genus of Retama is ...

Removal of Methylene Blue From Aqueous Solution Using Activated Rice Husk Biochar: Adsorption Isotherms, Kinetics and Error Analysis

“…The percentage reduction of adsorption infers competition between the similar charges on both surface of adsorbent and sorbate. Other studies [3,41] on lignocellulosic wastes and retama raetam plant both recorded maximum adsorption at pH 8 but their minimum was at pH 4 and 2 respectively. The differences could be that buffered solution was used and could have interfered with the adsorption process.…”

“…The careless and indiscriminate deposition in water bodies, in refuse dumps and combustion of the agricultural solid wastes poses serious threat to ecosystem. The quality of aquatic system including flora and fauna, soil and soil micro-organisms, air and aesthetics are affected adversely presenting itself as a serious environmental concern [1][2][3][4] . Recently, the development and use of various adsorption materials, techniques and technologies for the removal of contaminants from aqueous media have increased [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] .…”

“…The quality of aquatic system including flora and fauna, soil and soil micro-organisms, air and aesthetics are affected adversely presenting itself as a serious environmental concern [1][2][3][4] . Recently, the development and use of various adsorption materials, techniques and technologies for the removal of contaminants from aqueous media have increased [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] . Many researchers [15][16][17][18][19][20][21][22][23][24][25][26][27] have used many agricultural based waste materials such as Retama Raetam plant, saw dust, wheat bran, Jatropha Curcas and Terminalia Catappa and unmodified saw dust as an alternative cheaper and affordable substitute for application as sorbent for adsorption of contaminants from aqueous media.…”

Removal of methylene blue from textile waste water using kaolin and zeolite-x synthesized from Ethiopian kaolin

“…Among these, the textile industry is one of the major industries in the country, largest water consumer and wastewater source. The wastewater generated from textile factories is linked to one of the main water pollution problems [2]. Wastewater of this industry includes chemicals, suspended solids, toxic compounds, and dyestuff, which are one of the most attention required wastewaters.…”

Synergistic Effect of dark and photoreactions on the removal and photo-decolorization of azo carmosine dye (E122) as food dye using Rutile- TiO2 suspension

“…The negative ΔS o magnitudes without and with the using Fento reaction are -0.025 kJ mol -1 and -0.0312 kJ mol -1 respectively, the entropy for using Fenton reaction is less value and favor in adsorption reaction. The low values of entropies can be indicated to the associative adsorption mechanism has happened without a change in the internal structures of the catalyst (TiO2)and strong binding of dye ions onto the active sites [39,40]. Based on figure 5, The positive values of ΔG o without and with the using Fenton reaction are ranged to (3.518-3.830) kJ mol -1 and (3.954-4.691) kJ mol -1 with the raising the temperature ensures the processes are exothermic, non-spontaneous [36,37].…”