University of Tehran Researchers Trying to Settle Caspian Sea Pollution Problem

“Flocculation, as a natural self-purification mechanism, plays an important role in removing metals from water and transferring them to sediments, and the present study, by simulating the conditions in the laboratory, investigated the effect of ORP and salinity on the flocculation of lead (Pb), zinc (Zn), nickel (Ni), copper (Cu), and manganese (Mn) metals,” “The results showed that under normal conditions, Zn had the highest flocculation rate of 51.3% and Pb had the lowest removal rate of 2.5%. The increase in ORP led to significant changes in the behavior of metals, with the flocculation rates of Pb, Mn, and Ni increasing by 21.6%, 11.3%, and 8.8%, respectively, while Zn and Cu experienced a decrease of 4.1% and 2.4%, respectively,” said Abdolreza Karbasi, the head of the research group.

Noting that these differences indicate that salinity and ORP have a reciprocal effect on the flocculation process and that the behavior of each metal depends on its chemical properties, he said, "The mobility of metals in sediments was also affected by ORP and pH. An increase in ORP or a decrease in pH increased the mobility of metals, and the order of mobility was observed as Mn > Ni > Zn > Pb > Cu.”

“The risk assessment of metal mobility (RAC) showed that Mn was in the moderate risk category with the highest mobility, while Cu showed the lowest mobility. Also, the increase in ORP led to an increase in RAC values for all metals, indicating an increased probability of their release under oxidizing conditions,” Karbasi said.

Stressing that the research indicates the importance of ORP and salinity in controlling the fate of heavy metals in contaminated environments, he stated, "The findings show that changes in oxidation-reduction conditions can have a direct impact on the efficiency of natural processes such as flocculation."

In a relevant development in April, Iranian technologists at a knowledge-based company had also succeeded in finding a solution for managing and cleaning up oil pollution biologically by identifying and purifying eight bacterial strains and registering them in the gene bank.

The knowledge-based company started its research in the field of recycling wastewater and waste from drilling rig activities and, by achieving waste management technology and cleaning up oil pollution biologically, succeeded in purifying eight bacterial strains and registering them in the gene bank.

These technologists of the Iranian firm studied the most optimal conditions for cultivating these strains for inoculation in the main field by conducting research and experiments, and ultimately, two strains of these bacteria were produced and industrially cultivated and propagated as the best strains for degrading petroleum hydrocarbons.

These bacterial strains consume petroleum hydrocarbons, all of which are native to the region and have been isolated for the first time.

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