The adsorption of phosphate using a magnesia–pullulan composite: kinetics, equilibrium, and column tests

Abstract

Amagnesia-pullulan (MgOP) composite has been developed to remove phosphate from a synthetic solution. In the present study, the removal of phosphate by MgOP was evaluated in both a batch and dynamic system. The batch experiments investigated the initial pH effect on the phosphate removal efficiency from pH 3 to 12 and the effect of co-existing anions. In addition, the adsorption isotherms, thermodynamics, and kinetics were also investigated. The results from the batch experiments indicate that MgOP has encouraging performance for the adsorption of phosphate, while the initial pH value (3-12) had a negligible influence on the phosphate removal efficiency. Analysis of the adsorption thermodynamics demonstrated that the phosphate removal process was endothermic and spontaneous. Investigations into the dynamics of the phosphate removal process were carried out using a fixed bed of MgOP, and the resulting breakthrough curves were used to describe the column phosphate adsorption process at various bed masses, volumetric flow rates, influent phosphate concentrations, reaction temperatures, and inlet pH values. The results suggest that the adsorption of phosphate on MgOP was improved using an increased bed mass, while the reaction temperature did not significantly affect the performance of the MgOP bed during the phosphate removal process. Furthermore, higher influent phosphate concentrations were beneficial towards increasing the column adsorption capacity for phosphate. Several mathematic models, including the Adams-Bohart, Wolboska, Yoon-Nelson, and Thomas models, were employed to fit the fixed-bed data. In addition, the effluent concentration of magnesium ions was measured and the regeneration of MgOP investigated.

Fixed-Bed Column Technique for the Removal of Phosphate from Water Using Leftover Coal

“…The model does not require explicitly elaborated information about the characteristics of adsorbate and its type [ 52 ]. It rather predicts 50% of the breakthrough time and simulate the column data obtained from single adsorbate system [ 15 ]. The linear form of the model can be expressed by Equation (10) [ 48 ].…”

“…There are numerous methods to remove phosphate from water, including chemical precipitation, biological treatment, physical process, coagulation, and adsorption [ 12 , 13 , 14 , 15 ]. Nevertheless, most of them, with the exception of adsorption, show drawbacks due to the high sludge production, the complexity of the process, and high operational costs compared with adsorption methods [ 16 , 17 ].…”

Radiation Synthesis of Pentaethylene Hexamine Functionalized Cotton Linter for Effective Removal of Phosphate: Batch and Dynamic Flow Mode Studies

“…Bohart–Adams, Thomas and Yoon–Nelson models were used for describing and analyzing the laboratory-scale column, which linear forms were presented in the following Equations (10)–(12), respectively [4,38,39]. lnfalse(CtC0false)=knormalAnormalBC0normalt−knormalAnormalBN0ZF lnfalse(CtC0−1false)=KnormalTnormalHq0normalmv−KnormalTnormalHC0normalt lnfalse(CtC0-Ctfalse)=knormalYnormalNnormalt−τknormalYnormalN where C 0 was the influent and C t was the leakage concentration (mg/L) at time t; k AB , k TH and k YN were the model constants; t was the processing time; q 0 was the adsorption capacity; v was the flow rate; m was the adsorbent mass; N 0 is the saturation concentration; Z was the bed depth of column and F was the superficial velocity defined as the ratio of the volumetric flow rate Q to the cross-sectional area of the bed A.…”

“…Adsorption is considered an efficient technique for removing low-concentration contamination from wastewater. The advantages of adsorption are simple in design and operation, cheap to implement and effective at low concentrations [3,4].…”

Evaluation of phosphate adsorption by porous strong base anion exchangers having hydroxyethyl substituents: kinetics, equilibrium, and thermodynamics

“…Various approaches for physico-chemical removal of phosphate have been inspected, such as membrane processes (Zhao and Chen 2016), chemical precipitation (Nassef 2012), biological treatment (Bassin et al 2012), and adsorption techniques. Among these, adsorption seems friendly with the environment and easier to operate compared with the other techniques (Dragan and Dinu 2020;Ye et al 2019). The most investigated sorbents for their performances in phosphate removal could be grouped in (1) biomass-derived sorbents (Karthikeyan et al 2019;Wilson 2016, 2017), (2) inorganic oxides (Hao et al 2019;Jing et al 2020;Liu et al 2011;Wu et al 2019), (3) composite sorbents (Dragan et al 2019;Du et al 2020;Jia et al 2020;Li et al 2019;Liao et al 2020;Luo et al 2018Luo et al , 2019Rashid et al 2017;Wan et al 2017;Zong et al 2018), and (4) ion exchangers (Ding et al 2012;Liao et al 2020;Liu et al 2013; Responsible Editor: Tito Roberto Cadaval Jr Sowmya and Meenakshi 2014;Wei et al 2015;Zarrabi et al 2014;Zhu et al 2017).…”