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 ArticleBUNCH NUMBER AND ANTIOXIDANT ACTIVITY IN ‘SAHEBI’ AND ‘HALAGHO’ GRAPES AFFECTED BY PRUNING INTENSITY AND CANE LENGTH
Pruning methods can primarily affect grape production at various levels. Of the commonly affected features by pruning, the number of bunches has known to have a significant effect on the relation between the functions of assimilate sources and sinks. Further, fruitfulness can significantly be negatively influenced by shading. In this study, we aim to study the impact of 4, 6 and 8 buds per cane with pruning intensity as light, moderate and severely pruned and their interaction in the course two consecutive years, 2017 and 2018 in ‘Sahebi’ and ‘Halagho’ (both seeded red table grape cultivars). In 2018, lightly pruned ‘Halagho’ and having 8 buds per cane increased number of bunches by 54.00, which had the highest value. Results showed that there is apical buds bear more fruit by comparison to the buds with vegetative nature, 1 to 4 first buds. Based upon the outcomes of this study, it could be concluded that due to the stresses imposed by the pruning of the vines, therefore, the chemical compounds increases in order alleviate the negative aftermaths . In 2018, whole berry antioxidant activity in both cultivars was significantly lessened, and this decline was higher in ‘Saahebi’. The number of bunches was increased by increasing cane length or bud load/cane. Overall, the pruning program has an impactful role in bunch number as well as antioxidant activity and in the long-run on accumulated reserves, which makes choosing and applying a specific pruning method undeniably important. Thus, emphasize the importance of further research in this field.
Read ArticleCOMPARISON OF THE EFFECT OF SILICON AND SILICON NANO-CHELATE IN REDUCING THE IMPACT OF SALINITY STRESS ON WHEAT SEEDLINGS
Today, salinity stress causes extensive damage to crops, and high soil salinity is one of the limiting factors for crop yields. A practical approach to lessen the negative effect of salinity stress is to use mineral nutrition methods such as spraying plants with silicone. To investigate and compare the effect of silicon and silicon nano-chelate on the wheat plant resistance (Shiroodi cultivar) to salinity stress, a factorial experiment was designed and conducted in a completely randomized design with five replications under hydroponic conditions. Experimental treatments included concentrations of 0 and 2 mmol/L silicon, 0 and 0.424 g/L silicon nano-chelate, 0 and 150 mmol/L sodium chloride, and their interaction. The growth and physiological indices showed that salinity stress decreasing effect on shoot dry weight, root fresh weight, catalase activity, and ascorbate peroxidase. These increases indicate the activation of the plant defense system against salinity stress conditions. The results also showed that silicon nano-chelate treatment under salinity stress reduced dry and fresh weights of roots and shoots. These two compounds additionally influenced the content of catalase activity, ascorbate peroxidase, and superoxide dismutase content in shoots. Simultaneously, the silicon and silicon nano-chelate treatment under salinity stress reduced the dry and fresh weight of roots and shoots, catalase activity, and ascorbate peroxidase. Therefore, the results obtained in this study generally showed that silicon under salinity stress increased plant growth and positively affected the activity of its antioxidant system. But silicon nano-chelate not only did not improve plant performance but also reduced its growth.
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