Determination of ionic strength due to magnesium sulfate heptahydrate in water by means of its permittivity in the microwave range

Abstract

The ionic strength (I) of a solution is a measure of the concentration of ions or a measure of the intensity of the electric field in a solution. In water treatment, the ionic strength allows the determination of total dissolved solids concentrations. In this work, different concentrations of MgSO₄*7H₂O in water are considered. This produces several levels of ionic strength. This varies from 0 M to 0.20 M. The ionic strengths of liquid samples are determined by means of their permittivities in the microwave frequency range. The dielectric constants do not exhibit significant differences within the measured frequency range; however, the loss factors show significant differences at low frequencies. The loss factors at 500 and 915 MHz are used to determine the ionic strength due to MgSO₄*7H₂O. The relationships between ionic strength and loss factor obey to second-grade polynomials. The results presented in this work contribute to the development of tools that allow the monitoring of water in real time and in a non-invasive way.

Keywords:

• Permittivity
• ionic strength
• sensor
• microwave

Acknowledgment

The authors would like to thank Conacyt for the support of the project.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Edel Serafín Hernández Gómez

Edel Serafín Hernández Gómez received the B.Sc. degree from the Technologic Institute of Minatitlan, Veracruz, Mexico in 2012. In 2014, he received the M.Sc. Degree from the National Institute of Optical Astrophysics and Electronics, Puebla, Mexico, where he is currently working toward the Ph.D. degree. His research interests include material characterization using microwaves and electromagnetic compatibility.

José-Luis Olvera-Cervantes

José-Luis Olvera-Cervantes received the B.Sc. degree in Mathematics and Physics from the Instituto Politécnico Nacional (IPN), Mexico City, Mexico, and the M.Sc. and Ph.D. degrees from the Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Baja California, Mexico, in 2005 and 2008, respectively. He is currently a full professor in the Electronics Department at the Instituto Nacional de Astrofísica, Óptica y Electrónica (INAOE-Mexico). His research is focused on microwave systems, microwave imaging systems, microwaves for food applications, dielectric sensors, microwave devices, etc.

Benito Corona Vásquez

Benito Corona Vazquez received the B.Sc. degree in Civil Engineering from Universidad de las Américas Puebla (MEX) in 1996, and the M.Sc. and Ph.D. degrees from the University of Illinois at Urbana-Champaign, USA in 2001 and 2003, respectively. In research, its areas of interest are the development of alternative methodologies for the treatment of drinking and residual water in rural communities of Latin America, in addition to the understanding of the mechanisms involved in microbiological inactivation with chemical, physical and sequential disinfection.

Alonso Corona Chávez

Alonso Corona Chavez received the Ph.D. degree in electrical engineering from the University of Birmingham (UK) in 2001. From 2001 to 2004 he was with cryosystems (UK) as a Microwave Engineer. Since 2004 he is a researcher at the Instituto Nacional de Astrofisica, Óptica y Electrónica (INAOE-Mexico). He has been visiting professor at the University of California at Los Angeles, USA (2010), Queens University, Canada (2014) and the University of Guanajuato, Mexico (2016). His research is focused on microwave passive components and dielectric properties of materials.

Laura Sol Perez Flores

Laura Sol Pérez Flores received the PhD. degree in water sciences and Master's degree in Chemical Engineering from Universidad de las Américas Puebla (UDLAP) (MEX) in 2017 and 2012. Her research is about the improvement of water quality. Specialty on electrochemical treatments, focus on application of electrocoagulation in wastewater.

Tejinder Kaur Kataria

Tejinder Kaur Kataria received the B.S. degree in electronics engineering from Punjab Technical University in 2003; the M.S. degree in electronic engineering in 2007, and the Ph.D. in electrical engineering in 2011, from Instituto Nacional de Astrofisica, Óptica y Electrónica (INAOE-Mexico). From 2011 to 2015 she was a lecturer at the University of Las Americas (Mexico). In 2015 she was a postdoctoral researcher at Instituto Nacional de Astrofisica, Óptica y Electrónica (INAOE-Mexico). From 2016 she is a professor at the University of Guanajuato (Mexico).