Sustainable Energy & Chemical Engineering

Sustainable Energy & Chemical Engineering

Nitrate adsorption from synthetic aqueous solutions by Ca(OH)2 and clinoptilolite zeolite nano-particles

Document Type : Original Article

Authors
Faezeh Ghodrati 1
Azadeh Hemmati 2
Morteza Faghihi 3
Ziba Ashrafi 4
1 MIHAN Industrial Group, Tehran, Iran.
2 Semnan University, Semnan University
3 Chemistry & Process Engineering Department, Niroo Research Institute, Tehran, Iran
4 Mohaghegh Ardebili University, Ardebil, Iran
10.22075/jpetk.2024.25827.1006
Abstract
In this research article, the authors utilized a ball mill to grind Clinoptilolite zeolite 98% and Ca(OH)2 nanoparticles, and subsequently characterized the resulting adsorbents using SEM, TEM, XRD, and FTIR analyses. To optimize the adsorption process, they employed the Box-Behnken Design (BBD) of Response Surface Methodology (RSM) to evaluate the impact of various parameters, including pH (ranging from 5 to 9), adsorbent amount (ranging from 0.5 to 2 g), and temperature (ranging from 25 to 45 °C). The authors determined that the optimal temperature for nitrate adsorption was 45°C at a pH of 5, using 2g of adsorbent. Applying the pseudo-second-order dynamic model for investigation, the optimal retention time was determined to be 15 min. The maximum amounts of nitrate removed by Ca(OH)2 and zeolite were found to be 60.34% and 58.04%, respectively, with the the absorption equilibrium equation fitting well to the Langmuir model. Under optimal conditions, a mixture of Ca(OH)2 and zeolite (at a ratio of 1:3) removed a maximum of 56.70% of nitrates. These findings demonstrate the significant potential of natural zeolite and Ca(OH)2 for nitrate adsorption.

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Keywords
Adsorption
nitrate
Ca(OH)2
zeolite
nano-particles