Removal of Acidic Dye from Aqueous Solution Using Surfactant Modified Bentonite (Organoclay): Batch and Kinetic Study

Saraa M Ibrahim,Ziad T Abd Ali

doi:10.31026/j.eng.2020.05.05

Abstract

Modified bentonite has been used as effective sorbent material for the removal of acidic dye (methyl orange) from aqueous solution in batch system. The natural bentonite has been modified using cationic surfactant (cetyltrimethyl ammonium bromide) in order to obtain an efficient sorbent through converting the properties of bentonite from hydrophilic to organophilic. The characteristics of the natural and modified bentonite were examined through several analyses such as Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and Surface area. The batch study was provided the maximum dye removal efficiency of 88.75 % with a sorption capacity of 555.56 mg/g at specified conditions (150 min, pH= 2, 250 rpm, and 0.5 g/100 ml). The-results-showed that with the Freundlich isotherm model the sorption data was accurately described with (R2≥0.94) in comparison with the Langmuir model under the studied conditions. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.

Highlights

‫تم في هذه الدراسة تم استخدام مادة البنتونيت المعدل كمواد مازة منخفضة التكلفة وفعالة لإزالة الصبغة الحامضية (الميثيل‬ ‫ تم تعديل البنتونيت الطبيعي باستخدام منشط السطح الموجب‬.)‫البرتقالي‬ ‫ تم فحص خصائص‬. ‫لتكوين مادة ممتزة فعالة من خلال تحويل طبيعته من مادة محبة للماء الى مادة محبة للمواد العضوية‬
The modification of clay surfaces enhances their adsorptive properties through converting its nature from hydrophilic to organophilic, the modified of bentonite has high potential for alternate adsorbents to the most commonly used (Jiuhui, 2008)
The main objective of this study is to evaluate the possible application of modified bentonite as inexpensive and effective adsorbent material for the removal of methyl orange dye from aqueous solutions using batch experiments

Summary

Materials

Characteristics Physical Particle size, mm Moisture content, % Bulk density, kg/m3 Specific surface area, m2/g CEC, meq/100g Composition (wt%) Silica(SiO2) Aluminum(Al2O3) Ferric oxide(Fe2O3) Magnesium oxide (MgO) Calcium oxide(CaO) Sodium oxide(Na2O) Potassium oxide(K2O) Titanium oxide(TiO2) Loss on ignition (L.O.I). The different amount of modified surfactant (0.05, 0.1, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45 and 0.5g CTAB/1g natural bentonite) added to determine the best ratio of “CTAB/bentonite” that gives the highest MO removal efficiency. Figure showed the removal percent of MO from,aqueous,solutions,as a,function,of adsorbent at different ratios of surfactant (CTAB) for specific conditions (Co=100 mg/L, time=180 min, pH=7, agitation speed=200 rpm, dosage=0.2g) at 25 °C. the results showed that the removal efficiency was,increased with increasing the amount of CTAB because the positive charges of surfactant covered the surface of natural bentonite which lead to increase electrochemical interactions between the surface of modified clay and anionic dye molecules (Huang, et al, 2017; Jeeva and Wan Yaacob, 2018). The natural bentonite was tested for the removal of MO from aqueous solution; it found that the modified bentonite was 4.9 times adsorption capacity than natural bentonite. Co=100 mg/l, time=180 min ,dose=0.2g /100ml, pH=7, agitation speed=200 rpm Removal %

Characterization of bentonite

Findings

CTAB-bentonite dose