21-05-2025
A novel design of microbial desalination
MUSCAT: Winning in the Environmental and Biological Resources field in the Young Researcher's category, 'Desalination and acid-base recovery in a novel design of microbial desalination and chemical recovery cell' by Eng Azhar bint Juma Hamdan al Hinaiyah, Head of Waste Management Section in Environment Authority, was among the winning innovative research projects in the 11th National Research Award, organised by the Ministry of Higher Education, Research and Innovation.
Discussing the reasons behind the study, Eng Azhar al Hinai mentioned that microbial desalination cell (MDC) is deemed as an environmentally friendly technology for water treatment using organic matters present in wastewater for the desalination process. Microbial desalination and chemical recovery cell (MDCC) is a modified version of MDC that desalinates saline water using wastewater as fuel, generates electricity and concurrently produces value-added products. However, several factors have limited the MDCC performance and its development, eg, pH imbalance, ions accumulation and high internal resistance.
Eng Azhar elaborated that MDCCs, so far, are fabricated through modifying the dual-chamber microbial fuel cell (MFC) by placing the desalination and recovery chambers between the anodic and cathodic chambers, which not only increases the distance between two electrodes, but also brings different types of membranes between them leading to high internal resistance.
Therefore, this research, for the first time, demonstrated a novel design of MDCC, which is a modified version of a single chamber membrane-less MFC, named SMDCC; with the focus of removing barriers between the anode and cathode while upholding desalination and chemical recovery features of MDCC. The study focused on assessment of SMDCC performance in terms of electrolyte pH, acid and base recovery and desalination rate at different salt concentrations and in absence and presence of applied power supply.
For the main findings, Eng Azhar stated that this study proposed a new configuration for the microbial desalination and chemical recovery cell. The performance of the system in terms of electrolyte pH, acid and base recoveries and desalination rate were assessed comprehensively. She added that the results showed that the pH of the anode-cathode chamber of SMDCC was stable over the operation due to the absence of membranes between the anode and the cathode. In the case of 10 g/L salts concentration and in the absence of the external power supply, the pH of the HCl production chamber decreased to 3.029 and the pH of the alkali-production chamber increased to 8.96.
Furthermore, at high salt concentrations of 35 g/L, the acid and base recovery were enhanced (pH of 2.79 for acid and 9.41 for base pro duction chamber). The chemical recovery rate increased to 1.96 mg/h of acid and 1.48 mg/h for the base when 1.0 V of external voltage was applied. These results demonstrated the proof of concept for simultaneous desalination and chemicals recovery from a sustainable desalination system which is a modified version of single chamber membranelles MFC.
Eng Azhar pointed out that further investigations on the ion transport mechanism and detailed comparative analysis between single and dual-chamber modified MDCCs could enlighten more aspects of this new configuration.
This particular study, according to Eng Azhar, is contributing to achieve the national goals of the environment and natural resources priority in Oman Vision 2040 as it applies the concept of circular economy and use of renewable source of energy.
This research project was published in the journal Sigma-Aldrich, Scopus and Elsevier. The research team consist of Eng Azhar, Dr Abdullah al Mamun, Dr Tahereh Jafary, Eng Halima bint Khalifa Saif al Himaliyah, and Dr Sadik Rahman.
In regard to her win, Eng Azhar stated that 'this award has been a moment of immense pride and gratitude, symbolising the culmination of years of effort, perseverance and a passion for discovery. It is a profound honour that symbolises the recognition of hard work, creativity and dedication to advancing knowledge in the environment and natural resources field. It would serve as a reminder of the collaborative efforts and support from mentors, colleagues and teams that contributed to my journey. This is considered a great incentive for me to do more research studies that contribute to development and innovation of solutions to solve challenges in various sectors. It is also considered as evidence of the governmental effort in encouraging researchers and motivating them to publish scientific papers in various scientific journals. To me, it is more than a personal achievement, it is a testament to the power of curiosity and the importance of contributing something meaningful to society and the scientific community; and in shaping a better future for the next generation.'
