Journal of Environmental Treatment Techniques  
2019, Volume 7, Issue 2, Pages: 229-233  
J. Environ. Treat. Tech.  
ISSN: 2309-1185  
Journal web link:  
Treatment of Dye Wastewater by  
Functionalization of Bentonite-Methylene  
Blue with Sodium Persulfate  
2 3  
, Parveen Fatemeh Rupani , Loh Kar Woon , Mohd Hafiz  
4 2 2 3  
Asha Embrandiri  
Jamaludin , Mohd Azrul Naim , Jianzhong Sun , Weilan Shao and Suzy Ismail  
- Faculty of Agro-Based Industry, University Malaysia Kelantan, Jeli Campus, Kelantan, Malaysia  
- Biofuels Institute, School of Environment and Safety Engineering, Jiangsu University, Zhenjiang, China  
- School of Chemical Engineering, Universiti Sains Malaysia, Nibong Tebal, Malaysia.  
- Department of Biotechnology, Kulliyyah of Science, International Islamic University Malaysia, Kuantan, Malaysia.  
Received: 21/02/2019  
Accepted: 02/05/2019  
Published: 01/06/2019  
Bentonite has been effectively used in many studies for the removal of methylene blue (MB) laden waste waters. This is  
due to its high swelling ratio, good adsorptive properties and environmentally friendly characteristics. In spite of this,  
prolonged use renders the BMB non-functional and cause for discard. Sodium persulfate (SPS), has been reported to be an  
excellent flocculating agent for the functionalization of spent adsorbent due to some of its unique properties. In this study,  
the functionalization of spent bentonite-methylene blue (BMB) adsorbent in dye wastewater treatment was carried out using  
SPS at varying temperature conditions. Results revealed that the addition of SPS to MB-loaded adsorbent demonstrated  
efficient adsorption, high flocculation efficiency as well as faster equilibrium (60 min). The BMB loaded adsorbent showed  
5% removal efficiency up to three cycles. A plausible mechanism was proposed and discussed on the basis of the results.  
Thus, exhausted BMB was found to be effectively used for treatment of coloured wastewater on an industrial scale.  
Keywords: Bentonite; Methylene blue; Sodium persulfate; Dye wastewater; Functionalization.  
of other industrial applications as well (9).  
Triarylmethane is also very useful in the laboratories for  
staining purposes in microbiology and histo-pathological  
The textile industry utilises enormous volumes of  
water as a medium range mill uses about 1.6 million  
litres of water per day (1). Textile wastewater has  
become a major cause of water pollution due to the  
increasing the demand of textile products as well as the  
utilization of synthetic dyes (2). Owing to the high  
stability and extreme conditions, huge quantities of dyes  
are not eliminated during conventional wastewater  
treatment processes and remain in the ecosystem (3). Azo  
dyes from the textile industry are reported to be  
recalcitrant during their biodegradation and often  
perceived as xenobiotic (4). In spite of this,  
environmental legislation has made it mandatory for  
industries to eliminate colour from their dye effluents  
before discharge (5). Therefore, the textile industries  
have received considerable attention in the recent years  
In recent times low-cost adsorbents are being sought  
after as the alternative for activated carbon in waste  
water treatment (8, 10). These adsorbents are most often  
natural materials, biosorbents and agricultural or  
industrial waste materials. Amongst all other natural  
materials, clay occupies a prominent position due to low  
costs, easy availability, good sorption properties and  
environmentally safe (10, 11). Adsorbents of clay origin  
(diatomite, kaolinite, bentonite and fullers earth) are  
utilized because of the presence of organic and inorganic  
molecules (12). Bentonite, composed of montmorillonite  
clay of the aluminum phyllosilicates group is a well-  
known adsorbent used in wastewater treatment due to its  
unique properties such as high porosity, surface area and  
of high adsorption capacity (13, 14). The adsorption of  
methylene blue on clay is controlled by the ion-exchange  
processes. This implies that the adsorbing capacity  
fluctuates with pH variation (15).  
Removal of organic pollutants, phenol and dyes is  
already an extensively studied area of waste water  
research (16-18). However, investigation on regeneration  
and recovery of adsorbed molecules on the adsorbent  
surface is an area which needs to be explored. The reuse  
of adsorbent is paramount to ensure an economical and  
environmentally friendly process (19). Adsorbents can be  
(6) with regards to effective removal methods.  
Triarylmethane (triphenylmethane) a universally used  
textile dye, makes up approximately 30%40 % of the  
overall dye consumption (7) and have been extensively  
applied on wool, cotton, silk and nylon (8). It is used for  
coloring food, paper, leather, plastics, waxes and a host  
Corresponding author: Asha Embrandiri, Faculty of  
Agro-Based Industry, University Malaysia Kelantan, Jeli  
Campus, E-mail: ORCID: 0000-0001-5038-3538.