Mukhtar Dhajir Shubber; Mohammed Kadhum Al kasser; Daryoush Yousefi Kebria
Abstract
The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, ...
Read More
The study aims to show the role of pH value and the feasible mechanisms that affect the adsorption capacity by the theoretical concept and experimental work. The protonation, ionization, hydrophobicity, dissociation, precipitation, hydrolysis, hydroxylation, electrical repulsion or interaction, ion exchange, and complexation and chelating are effective mechanisms that have been studied theoretically to show their essential role in the absorption process and how they are affected by the pH value. Moreover, using varied pH values (2, 4, 6.5, 9, 11, and 13) to verify experimentally the role of the studied mechanisms on the adsorption capacity utilizing the recycled bentonite waste as adsorbent to adsorb the heavy metals, methylene blue dye, and engine oil as adsorbates from aqueous solution. It was apparent that the pH solution has an influential role in the adsorption capacity and from the difficulty in predicting the effect without making the experimental investigations due to the nature of the adsorbent and adsorbate that affected the ten mechanisms where the pH of the high adsorption capacity for heavy metal was alkaline (>11) and for the methylene blue and engine oil was neutral(≈ 6.5).
Emeka Donald Anyanwu; Anthony Chukwubueze Okoboshi; Onyinyechi Gladys Adetunji; Florence Nneka Onyiwalu
Abstract
The levels of heavy metals in the environment have seriously increased during the last few decades due to human activities. Aquatic environment is a major recipient of heavy metal pollution. Heavy metal content of Ahi River was studied between May and October 2023 in three stations, compared with national ...
Read More
The levels of heavy metals in the environment have seriously increased during the last few decades due to human activities. Aquatic environment is a major recipient of heavy metal pollution. Heavy metal content of Ahi River was studied between May and October 2023 in three stations, compared with national standards to determine the water’s suitability for drinking. The water samples were collected and analysed using standard methods. The eight evaluated heavy metals and concentrations were: Iron (0.93-2.83 mg/L), Zinc (0.61-0.90 mg/L), copper (0.1-0.9 mg/L), lead (0.05-0.34 mg/L), chromium (0.08-0.64 mg/L), cadmium (0.03-0.21 mg/L), nickel (0.02-0.14 mg/L) and manganese (0.38-1.1 mg/L). All the metals exceeded limits for drinking water (except zinc and copper). The lowest and highest values for most of the metals were recorded in May and September 2023, respectively. However, station 3 had relatively high values in all the metals. The heavy metal content was influenced by geology, rainfall and human activities. Single factor pollution index (SFPI) and comprehensive pollution index (CPI) showed the water was polluted and unsafe while pollution load sharing rate (PLSR) showed that lead and cadmium contributed most to the pollution. The concentrations of the metals influenced the values of the indices, therefore, waters of Ahi River is not suitable for drinking but can be used for other domestic purposes.
