Evaluation of Natural and Calcined Eggshell as Adsorbent for Phosphorous Removal from Water

Abstract

Natural and calcined eggshell as adsorbent alternatives were evaluated for the removal of phosphorous from water. Calcined eggshell was obtained after treating the natural eggshell at 900 °C in electric furnace for 2 h. The examination on their characteristics was carried out with thermogravimetry and differential thermal analysis (TG/DTA), scanning electron microscope (SEM), X‐ray diffractometer (XRD), and energy dispersive X‐ray spectrometer (EDX). The working solution containing phosphorous was prepared by dissolving KH2PO4 with distilled water. The batch adsorption experiment was conducted by changing various variables such as initial phosphorous concentration, dosage of natural and calcined eggshell, contact time, and pH. It turned out that natural eggshell was unable to remove phosphorous from water, whereas a considerable amount of phosphorous by calcined eggshell was removed in initial contact time (0.25 h). The removal efficiencies were found to be 99.5 and 99.28% at experimental conditions of 5 mg/g of initial phosphorous concentration and a 1.0 g of calcined eggshell dosage, respectively. The removal efficiencies of phosphorous by calcined eggshell were dependent on the abovementioned variables. The difference in the removal behavior of phosphorous by natural and calcined eggshell may be explained due to the different pH values and Ca2+ concentration in solution. The research results suggested that phosphorous removal mechanism by natural eggshell is caused by adsorption of phosphate (as phosphorous source) onto the surface of natural eggshell, however, on the contrary to this, the phosphorous removal on calcined eggshell is arisen from the binding of phosphosphate and calcium resulting in precipitation of calcium phosphate. Experimental data were applied by the pseudofirst‐order and pseudosecond‐order kinetics models and Freundlich and Langmuir isotherm models, respectively. The pseudosecond‐order kinetics model and Langmuir isotherm model were more suitable for calcined eggshell owing to the higher correlation coefficient R2. In conclusion, the result showed that calcined eggshell could become a favorable adsorbent material for removing phosphorous from water.

A coagulation-flocculation process combined with continuous adsorption using eggshell waste materials for phenols and PAHs removal from landfill leachate

“…A review of the literature reveals that the use of eggshell waste materials in their natural as well as chemically modified forms have provided excellent results for the removal of various classes of dyes [20,21], oxalic acid [22], phenols [23,24], pesticides [25], humic acid [26], heavy metals [27,28] fluorides [29], Phosphorous [30] and PAHs [31]. Most of these applications were tested on batch experiments and focused on synthetic wastewater; Limited work has been reported for the applicability of eggshell materials for the treatment of real wastewater or more specifically for the treatment of municipal landfill leachate [32].…”

Mesoporous Aluminosilicate Nanofibers with a Low Si/Al Ratio as Acidic Catalyst for Hydrodeoxygenation of Phenol

“…Moreover, the high content of water (above 50 wt.%) in raw bio‐oil and its formation during HDO process are two additional factors to take into account . It is well known that pure mesoporous silica such as MCM‐41 and MCM‐48 are weakly resistant to harsh hydrothermal conditions . To increase their hydrothermal stability, surface modifications with hydrophobic moieties or aluminum species are often undertaken .…”

Thermal and Hydrothermal Stability of Hierarchical Porous Silica Materials

“…During the condensation and polymerization of TMOS, silanol groups are formed at the surface and the water adsorbed onto these silanol groups causes the hydrolysis of nearby Si–O–Si bonds, resulting in the gradual collapse of the ordered mesoporous structure , . To support this hypothesis, the different porous materials have been investigated by infrared spectroscopy.…”

“…As a result, the collapse of the mesoporous network occurs , , . In the case of the dual‐mesoporous material, because of the thinner walls, the small mesopores network is more subjected to the attack by water and collapses first.…”