QU researchers develop new green material for wastewater treatment

A research team from the Gas Processing Centre at Qatar University (QU) has developed a novel method to meet the need for green materials in the wastewater treatment field. The team comprising Prof Mustafa Nasser, research professor, Prof Ibnelwaleed Hussien, research professor, Prof Abdelbaki Benamer, research professor, and Dana al-Risheq, MSc environmental engineering graduate, alongside Prof Hazim Qiblawey from the Chemical Engineering Department at QU examined multiple green materials for the treatment of colloidal suspension-contaminated wastewater with very fine suspended particle.Coagulation/flocculation is a reliable and efficient technique to clarify colloidal suspension. It requires the addition of a chemical agent known as coagulant/ flocculant to bring the colloids in wastewater together forming larger particles that will settle down under the influence of gravity.“Currently, the chemical agents employed in the industrial field demonstrate some challenges regarding their limited efficiency and negative impacts on the environment. In this regard, it has become necessary to identify new environmentally friendly materials with greater treatment potential,” says an article on the latest issue of QU research magazine.“The investigation of the research team led to discovering the novel application of choline chloride based natural deep eutectic solvents (Nades) as a coagulant for colloidal suspensions. The research group was able to synthesise, characterise, test, and prove for the first time the effectiveness of choline chloride based Nades as a coagulant,” the article explains.Nades are chemical mixtures of naturally abundant components such as choline chloride, organic acids, amides, and sugars. They are known for their simple and time-efficient synthesis method, biodegradability, and non-toxicity. However, there were no studies on the applications of Nades for wastewater treatment. The research group led by Prof Nasser noticed the potential of using choline chloride based Nades in the coagulation/ flocculation process after analysing the chemical structure of the compound. “The similarity in Nades structure with polyacrylamide, which is a widely used flocculant in the industry, drove the research groups’ attention to investigate its treatment efficiency for colloidal suspensions. They proposed that the positive charge in the Nades structure will reduce the repulsive forces between the negatively charged colloidal particles. Hence, the particles will come together forming a greater mass that will settle with gravity and thus, separate the liquid and solid phases,” pointed out the researcher.The experiments were conducted using bentonite clay minerals to represent colloidal particles in suspension. Nades was synthesised from choline chloride and an organic acid with continuous mixing and heating until a homogeneous mixture is formed. “The efficiency of the synthesised Nades as a coagulant was determined according to specific criteria which include reduction in the turbidity of the treated suspension and the size of settled particles. The tested Nades was found to be highly efficient for the treatment of bentonite suspensions. It significantly reduced the turbidity of the system with a relatively small dosage. Furthermore, the size of the formed particles was sufficient for them to settle and produce clarified water within two minutes,” concludes the article.