Kinetics and Isotherm Modeling for the Treatment of Rubber Processing Effluent Using Iron (II) Sulphate Waste as a Coagulant

Abstract

There is increasing concern to determine an alternative coagulant for treating industrial effluent with minimal environmental impact and operational cost. In this study, iron (II) sulphate heptahydrate (FeSO4·7H2O) waste, an industrial byproduct from a titanium oxide processing industry, was used as a coagulant for the removal of ammonia (NH3), chemical oxygen demand (COD), biochemical oxygen demand (BOD), and suspended solid (SS) from secondary rubber processing effluent (SRPE). The highest percentage removal of BOD, COD, SS, and NH3 achieved was approximately 97%, 99%, 98%, and 95%, respectively, at pH 5.0, coagulant dose of 1 g/L, coagulation time of 60 min, sedimentation time of 60 min, and at an elevated temperature of 70 °C. The best described adsorption isotherm model was found to be the Brunauer–Emmett–Teller (BET) model, indicated that the FeSO4·7H2O adsorption took placed on the surface of iron hydroxide precipitates with multilayer formation and random distribution. The kinetics analysis showed that the adsorption mechanism was well fitted with the pseudo-second-order kinetic model. The findings of the present study show that the FeSO4·7H2O waste has the potential to be used as a coagulant for the treatment of industrial effluents, including the secondary rubber processing effluent.

Treatment of Palm Oil Refinery Effluent Using Tannin as a Polymeric Coagulant: Isotherm, Kinetics, and Thermodynamics Analyses

“…In addition, the coagulation isotherm modeling equations are effective in explaining coagulation behavior. Among these isothermal models, the Freundlich and Langmuir isothermal models are the most utilized isotherm model models to determine the nature of the coagulation process [ 13 , 24 , 26 ]. In the present study, Langmuir and Freundlich isotherm models were utilized to express the coagulation behavior of tannins on BOD, COD turbidity, and SS removal from PORE, as shown in Figure 6 .…”

“…The determination of the coagulation kinetics is important to predict the coagulation behavior of the colloidal and suspended organic particles present in the industrial effluent. Generally, the coagulation mechanisms for the elimination of the colloidal and suspended organic particles depend on the chemical characteristics of coagulant and mass transfer phenomena [ 13 , 31 ]. The coagulation kinetics describes the removal efficiency of the colloidal and suspended organic particles on the surface of the coagulant at each equilibrium contact time.…”

“…Wherein, the coagulation experiments were carried out with varying coagulation temperature from 30 to 80 °C as a function of slow mixing time from 5 to 90 min with a constant pH of 6.0, a constant rapid mixing time of 3 min, and a sedimentation time of 60 min. The pseudo-first-order kinetic model equation can be written as below [ 13 ]: where q e represents the BOD, COD, turbidity, and SS (mg/mg) removal from PORE at equilibrium; and q t signifies the BOD, COD, turbidity, and SS (mg/mg) removal from PORE at time t (min). k 1 signifies the pseudo-first-order coagulation rate constant (min −1 ).…”

“…This technology has been extensively utilized to treat various industrial effluents, including PORE, using various chemical-based commercial coagulants, such as alum, aluminum chloride, poly-aluminum chloride, and poly ferric sulfate. The distinct advantages of this process are the short treatment time, effective removal of both inorganic and inorganic pollutants, easy handling, and availability [ 11 , 13 ]. The major shortcoming of the coagulation process is the generation of hazardous sludge, which requires a costly disposal method.…”

“…The major shortcoming of the coagulation process is the generation of hazardous sludge, which requires a costly disposal method. The sludge generated in the coagulation process contains toxic metals ion due to the utilized alum, aluminum chloride, aluminum or based polymeric salts including poly-aluminum chloride (PAlCl), and polyferric sulfate as a coagulant [ 11 , 13 ]. Therefore, scientists are looking for natural polymer as an alternative to commercial coagulant for applications in environmental technologies, wherein tannin as a natural polymeric coagulant would be highly promising.…”