Adsorption of phosphate from aqueous solutions using waste mussel shell

Nur Atikah Abdul Salim,Muhammad Rijaluddin Khairuddin,Noorul Hudai Abdullah,Mohd Hafiz Dzarfan Othman,Mohd A’Ben Zulkarnain Rudie Arman,Mohd Hairul Khamidun,Mohd Hafiz Puteh,Abdull Rahim Mohd Yusoff,Mohamad Ali Fulazzaky,Yaacob Haryati,Ibrahim Izni Syahrizal,Mohd Yunus Nor Zurairahetty

doi:10.1051/matecconf/201825006013

Abstract

Excessive amount of phosphate released from wastewater can cause eutrophication to the receiving waters. Adsorption technique has been used to remove phosphate from aqueous solutions. The use of waste mussel shell (WMS) to remove phosphate from aqueous solutions and application of several kinetic and isotherm models to describe the adsorption of phosphate onto WMS were conducted in batch experiments. The phosphate adsorption by the WMS was examined with respect to solute concentration, contact time and adsorbent dose. The phosphate removal efficiencies obtained were 46.7, 57.6, 64.1, 70.8 and 75.2% at 144 h contact time for WMS dosage of 2, 4, 6, 8 and 10 g, respectively. Physical and chemical properties of WMS including surface physical morphology and elemental compositions were characterized. A comparison of kinetic models applied to the phosphate adsorption onto WMS was evaluated for the pseudo-first order and pseudo-second order model. The experimental data fitted very well with the pseudo-second order kinetic model (R2 > 0.984), which indicated the adsorption process was chemisorption. In the isotherm studies, the Langmuir and Freundlich isotherm models were applied. The results indicated that the use of Freundlich equation is well described with the phosphate adsorptions onto WMS (R2 = 0.968), suggesting the heterogeneity of the adsorbent surface. The experimental results suggested the use of WMS as an excellent adsorption material for phosphate removal from aqueous solutions, giving new insights into environmental engineering practices.

Highlights

The excessive amount of phosphate release from domestic wastewater may lead to degradation of the receiving water, and cause eutrophication process [1]
Surface morphology of waste mussel shell (WMS) was examined via scanning electron microscopy (SEM) and elemental composition of WMS was determined using Xray diffraction (EDX) instrument [8]
The elemental composition analysis of WMS was examined by EDX (Energy-Dispersive X-Ray Spectroscopy, Bruker, Model X Flash 6I10, German)

Summary

Introduction

The excessive amount of phosphate release from domestic wastewater may lead to degradation of the receiving water, and cause eutrophication process [1]. When a water body is enriched with phosphate, it can stimulate the growth of plants and algal blooms making the water to lost its important function and induce adverse effects on human health and environment [2,3]. According to the EU, the limit values of phosphorus for effluent discharge in wastewater treatment plants are in a range of 1.0-2.0 mg L-1 [5]. The effluent limit of total phosphorus according to USEPA Clean Water Act is 0.5-0.8 mg L-1 [6]

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