Textile Dye Removal using Dried Sun Flower Seed Hull a New Low Cost Biosorbent: Equilibrium, Kinetics and Thermodynamic Studies

Research Article

Adv Res Text Eng. 2016; 1(1): 1008.

Textile Dye Removal using Dried Sun Flower Seed Hull a New Low Cost Biosorbent: Equilibrium, Kinetics and Thermodynamic Studies

Oguntimein GB*

Department of Civil Engineering, Morgan State University, USA

*Corresponding author: Gbekeloluwa B. Oguntimein, Department of Civil Engineering, Morgan State University, USAt

Received: October 01, 2016; Accepted: November 11, 2016; Published: December 07, 2016


The adsorption capacity of a neglected biosorbent, Dried Sunflower Seed Hull (DSSH), was investigated in this study for methylene blue dye removal. The influences of some operating variables including dye concentration and contact time on the dye biosorption were investigated in batch mode. Adsorption kinetics were examined by first and second order rate models, and intra particle diffusion models, while equilibrium studies were examined by Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. D-R model fitted the data best with a biosorption capacity of 0.0365 mg/g. The standard Gibbs free energy change was also calculated to define the nature of biosorption process. These results revealed that the utilization of sunflower seed hull residues as dye biosorbent could be an interesting option from both environmental and economic point of view.


Dyes are important compounds commonly used in various industries such as textile, paper, leather and plastic manufacturers [1]. The textile-dyeing industry consumes large quantities of water and produces large volumes of wastewater from different steps in the dyeing and finishing processes. Wastewater from printing and dyeing units is often rich in colour. The presence of even very low concentrations of dyes in the effluent is highly visible and undesirable. The effluent also contains residues of reactive dyes and harmful chemicals. Therefore, such wastewater needs to be properly treated before its release into the environment [2]. Many structural varieties of dyes exist, including acidic, basic, disperse, azo, diazo, anthraquinone based and metal complex dyes [3]. Annual dye production is estimated at about 100, 000 commercially available compounds with more than 7 × 105 ton of dyestuff produced [4]. Consequently, textile industries produce vast amount of coloured wastewater due to low level of dye fiber fixation [5]. According to various dye classification, methylene blue is categorized as a highly toxic cationic dye [6]. Effluent dyes released from these industries constitute an important part of water pollution [7]. Disposal of untreated dye effluents has characteristics environmental effects due to the presence of toxic pollutants which are resistant to typical microbial biodegradation [8]. Most dyes are made recalcitrant compounds through their interaction with sunlight in the effluent wastewater and can transform to carcinogenic compounds under anaerobic conditions [9]. Such waste-water represents a large group of organic chemicals which could present health related risk to humans in excess amount [10]. Effluent dye wastewater is a large volume production which can supplement limited fresh water resources if properly treated [11].

Several treatment methods have been applied in the removal of dye such as chemical precipitation [12], reverse osmosis [13], ion exchange [14], solvent extraction [15] and ozonation [16]. However, these methods have significant drawbacks such as high capital and operational cost [17]. Adsorption method is an efficient and feasible wastewater treatment process which utilizes non-toxic, low cost and readily available adsorbents [18]. These adsorbents are effective against a wide range of pollutants and a potential alternative for costly processes. Adsorbents range from commercial to low cost materials such as activated carbon [19], peat [20], organoclay [21], peanut husk [22], peanut hull [23], pine sawdust [24], MIRHA [25, 26] and oil palm ash [27]. The environmental and cost advantages of non-conventional low cost adsorbents have prompted more research into this area. These advantages were summarized as follows:(i) Nonconventional adsorbent can compete favourably with conventional adsorbents in terms of efficiency depending on the characteristics and particle size of the adsorbents ,and the nature of the adsorbate. (ii) Non-conventional adsorbents are cost effective; require simple alkali treatment, less maintenance and supervision.

Materials and Methods

Preparation of Sunflower Seed Hull (SSH)

A 120 g packet of Sunflower seeds purchased from a local grocery was deshelled and the hull was milled in a coffee grinder. The milled hull was then separated into different particle seizes using with ASTM standard sieves with mesh seizes 60 (250μm aperture), 40 (425μm aperture) and 20 (850μm aperture). The fraction of the sunflower seed which is hull was determined by deshelling a known weight of seed and weighing the hull separated. The effect of acid and base treatment was studied using the fraction retained on the 40 mesh sieve. Three grams each of milled hull was soaked overnight in either 250 ml of 0.05M hydrochloric acid (HCl) or 250 ml of 0.05M sodium hydroxide (NaOH). The pHs of the supernatants were 1.36 and 12.66 respectively. The supernatant was removed and each fraction was washed thrice with 250 ml distilled water (dH2O). The pH of the acid treated Sunflower Seed Hull (SSH) was then adjusted to pH 5.0 with drops of 1M NaOH while the base treated SSH was adjusted to pH 5.5 with drops of 1 M HCl. The wet SSH was dried overnight at 70oC in a forced air drying oven to constant weight. The Dried Sunflower Seed Hull (DSSH) was used in the adsorption characteristics studies [28]. The sunflower plant is a native of North America. It was grown by the Indians for food in North Carolina before 1600 and by New England colonists for hair oil as early as 1615 [29]. The rising prominence of sunflower oil in world edible oil markets has stimulated increased interest in expanded U.S production for last decades. U.S acreage of sunflower planting has expanded rapidly in the 1970’s, reaching a peak at 5.5 million acres. The U.S sunflower production has declined in recent years. Currently U.S planted sunflower over 1.8 million acres in 2012 and approximately 1 million metric tons of sunflower seed were produced in 2011. 41% and 32.7 % of total sunflower planted acres were grown in the North Dakota and South Dakota in 2012, respectively [30]. Compared with soybean oil which currently dominates the US edible oils market, sunflower seed oil has a higher content of polyunsaturated fatty acids [29]. The world production of sunflower seed is 31.1 MT with the USSR being the largest producer producing 6.3MT, Ukraine 4.7MT, Argentina 3.7MT , China 1.9MT, India 1.9MT, USA 1.8MT [31]. The U.S produced around 6% of the world’s sunflower production and 85.1 % of total U.S sunflower production is for vegetable oils. In recent years, approximately 12 million acres of sunflowers have been grown in the world annually [32]. The hull accounts for 22 to 28% of the weight of sunflower seed and becomes a by product of the seed crushing operation. Large-seed varieties have higher proportion of hull than small-seed varieties. The most promising use for sunflower seed hulls appears to be as roughage ingredient for livestock feed. Sunflower hulls make coarse roughage, high in fiber but suitable for use in ruminant rations. Sunflower hull contains 11.5% moisture, 3.5% protein 3.4% fat and 22.1 % fiber [29].

The objectives of this study were to investigate the potential use of sunflower seed hull, as an effective biosorbent for the removal of methylene blue dye from aqueous solutions and study its thermodynamic and kinetic properties.

Preparation of dye solution

Methylene Blue (MB), the basic dye used as the model sorbate in the present study is a monovalent cationic dye. It is classified as C.I. Basic blue 9, C.I. solvent blue 8, C.I.52015. It has a molecular weight of 373.90. Methylene blue (MW 319.85 g/mole) was obtained from Sigma-Aldrich Milwaukee, Wisconsin USA. The chemical structure of MB is shown in Figure 1. A stock solution 1 mg/L was prepared by dissolving 0.05mg in 50 ml of distilled water. Various dilution of this stock solution was used for the batch studies. The experimental concentrations were obtained by dilution of this solution. 0.05M HCl or 0.05M NaOH was used for pH adjustment of the working solutions. The concentration of MB dye was measured at a wavelength of 664 nm using UV-Visible spectrophotometer (Gensys 5).