ADSORPTION STUDIES OF ZINC, COPPER, AND LEAD IONS FROM PHARMACEUTICAL WASTEWATER ONTO SILVER-MODIFIED CLAY ADSORBENT
Background: Industrial wastewater contains pollutants that are detrimental to human health in varied proportions. Among the pollutants are heavy metals, including Zn2+, Pb2+, and Cu2+ found in a characterized pharmaceutical wastewater. Several techniques have been proposed for the heavy metal sequester. However, they are with attendant challenges. The adsorption techniques using clay-metal oxide modified adsorbent/composite such as silver-clay adsorbent is considered suitable for an effective sequestering process. Aims: To develop and characterize Ag/clay adsorbent for pharmaceutical wastewater treatment. Methods: The Ag nanoparticles were synthesized using Parkia biglobossa aqueous leaves extract in an optimization study. The raw clay was beneficiated and doped with silver nanoparticles via the wet impregnation method. The silver-clay adsorbent was characterized using FTIR, XRD, SEM, and EDS characterization tools. The developed adsorbent was used for the batch adsorption process of the heavy metal ion removal from the wastewater. Results and Discussion: The phytochemical analysis and FTIR results of the P. biglobosa showed that the leaf contains phenol, tannin, and flavonoids which acts as reducing, capping, and stabilizing agent required for synthesizing the silver nanoparticles. The prepared silver nanoparticles modified clay adsorbent Ag/clay, have evenly distributed stacks of pseudo-hexagonal plates, are rich in silica, possess silver nanoparticles in the frameworks, and contain functional groups suitable for binding heavy metals. The adsorptions of Zn2+, Pb2+, and Cu2+ from pharmaceutical wastewater onto the silver-modified clay were studied as a function of adsorbent dosage and contact time. The percentage removal results obtained showed that the adsorbent had up to 99.96%, 99.5%, and 99.44% removal efficiency for Zn2+, Pb2+, and Cu2+, respectively, which are better compared with previous studies. The adsorption process was feasible, spontaneous, and exothermic, with Langmuir and Pseudo-second-order models as best fits for the process. Conclusions: The adsorption of selected heavy metal ions onto the green synthesized silver-modified clay adsorbent (Ag/clay) was feasible, spontaneous, and exothermic in the order Zn2+>Pb2+>Cu2+ with Langmuir and Pseudo-second-order model best fitted for the process. These show that the synthesized silver oxide nanoparticles supported on local clay can be used as a potentially low-cost adsorbent to remove heavy metal ions from industrial wastewater.
Read ArticleQUINOLINE DERIVATIVES AS GROWTH REGULATORS FOR ORNAMENTAL PLANTS
It is investigated the effect of synthesized organic compounds of 6-hydroxy-2,2,4-trimethyl-1,2- dihydroquinoline, its derivatives, and hydrogenated analogs. These compounds affected the height of seedlings when they were used for pre-sowing seed treatment of the following ornamental plants: annual ornamental grass – scarlet sage (Salvia splendens) and woody plant – yellow rhododendron (Rhododendron luteum). Prior to the sprouting process, the seeds of Rh. luteum and S. splendens were soaked in water solutions of compounds with concentrations of 0.01%, 0.05%, and 0.1% for 18 hours. Dihydro- and tetrahydroquinolines with a concentration of 0.05% proved to be the most effective for both plants. For Rhododendron luteum, the compounds of 6-hydroxy-2,2,4-trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs with a concentration of 0.1% proved to be the most effective. Dihydroquinolines at concentrations of 0.05 and 0.1% proved to have the strongest effect when applied to the studied perennial woody plant (Rhododendron luteum). Dihydroquinoline at the concentration of 0.05% also proved to be effective when applied to the annual grass (Salvia splendens). For annual S. splendens, tetrahydroquinoline at concentrations of 0.01 and 0.05% appeared to be the most effective. The pre-sowing seed treatment of grass Salvia splendens and woody plant Rhododendron luteum with the studied compounds demonstrated that their effect on the height of the seedlings is species-specific. The pre-sowing seed treatment of Rh. luteum and S. splendens allows increasing the height of the seedlings by 3-61 % and 17-25 %, respectively. It is suggested using the compounds of 6-hydroxy-2,2,4- trimethyl-1,2-dihydroquinoline, its derivatives, and hydrogenated analogs as effective growth stimulators for ornamental grasses and woody plants.
Read ArticleUSING SYNTHESISED ORGANIC COMPOUNDS AS ENVIRONMENTALLY FRIENDLY RETARDANTS FOR ORNAMENTAL PLANTS
The pre-sowing treatment of scarlet sage (Salvia splendens Ker Gawl.) seeds with 4-methyl-2-piperidin1-yl-pyrimidine-5-carboxylic acid at concentrations of 0.01, 0.05, and 0.1% proved to have an obvious inhibiting effect. Prior to sowing, the seeds of Salvia splendens were soaked in a water suspension of 4-methyl-2-piperidin-1-yl-pyrimidine-5-carboxylic acid and 4-methyl-2-morpholin-4-pyrimidine-5-carboxylic acid with concentrations of 0.01%, 0.05%, and 0.1% for 18 hours. On the 42nd day of the experiment, the seedlings, having been preliminarily hardened for 12 days, were removed from the greenhouse and planted on the field. The pre-sowing treatment of Salvia splendens seeds with 4-methyl-2-morpholin-4-pyrimidine-5-carboxylic acid proved to have the inhibiting effect at concentrations of 0.01 and 0.05%. The height of the seedlings decreased by 13.3-43.7%. It was revealed that 4-methyl-2-piperidin-1-yl-pyrimidine-5-carboxylic acid at concentrations of 0.01, 0.05, and 0.1% decreased the growth of the seedlings by 30.4-43.7%, and 4-methyl-2-morpholin-4-pyrimidine-5-carboxylic acid at concentrations of 0.01 and 0.05% decreased the growth of the seedlings by13.3-22.2%. By contrast, the effect of pyrimidinecarboxylic acids on seed germination and plant height of another annual flower – spreading marigold (Tagetes patula L.) was stimulating. It was investigated some different concentrations from 0.01 to 0.05 %. The same concentrations of identical compounds were tested, but effects from them were opposite for Tagetes patula, and Salvia splendens seedlings. Сonsequently, the species-specific effect of pyrimidinecarboxylic acids on seed germination and plant height for ornamental grasses takes place. Therefore,4-methyl-2-piperidin-1-yl-pyrimidine-5-carboxylic acid and 4-methyl-2-morpholin4-pyrimidine-5-carboxylic acid are recommended as growth retardants for Salvia splendens.
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