Synthesis of Indonesian Kaolin-nZVI (IK-nZVI), Evaluation for the Removal of Pb(II) from Waste Streams

Removal of toxic pollutants such as heavy metals from wastewater is of utmost importance in the current century. Heavy metals have severed a big problem in the world. Several tools have been established to mitigate this problem. In this research paper, Indonesian Kaolin-nano zerovalent iron (IK-nZVI) was synthesized as a model adsorbent for Pb(II) removal from wastewater. The efficiency of IK supported nZVI for Pb(II) removal efficiency was estimated by accompanying batch experiments. The examined parameters included the amount of IK-nZVI, the concentration of Pb(II) removal and the effect of pH. The results revealed that the IK-nZVI was efficient for the removal of Pb(II) from waste water. © 2020 Author(s).The author Lakkaboyana Sivarama Krishna is grateful to the Graduate School and The Thailand Research Fund (IRG578001), Chulalongkorn University for providing financial support, Senior Postdoctoral Fellowship under Rachadapisaek Sompote Fund

Ranking of gridded precipitation datasets by merging compromise programming and global performance index: a case study of the Amu Darya basin

Accurate representation of precipitation over time and space is vital for hydro-climatic studies. Appropriate selection of gridded precipitation data (GPD) is important for regions where long-term in-situ records are unavailable and gauging stations are sparse. This study was an attempt to identify the best GPD for the data-poor Amu Darya River basin, a major source of freshwater in Central Asia. The performance of seven GPDs and 55 precipitation gauge locations was assessed. A novel algorithm, based on the integration of a compromise programming index (CPI) and a global performance index (GPI) as part of a multi-criteria group decision-making (MCGDM) method, was employed to evaluate the performance of the GPDs. The CPI and GPI were estimated using six statistical indices representing the degree of similarity between in-situ and GPD properties. The results indicated a great degree of variability and inconsistency in the performance of the different GPDs. The CPI ranked the Climate Prediction Center (CPC) precipitation as the best product for 20 out of 55 stations analyzed, followed by the Princeton University Global Meteorological Forcing (PGF) and Climate Hazards Group Infrared Precipitation with Station (CHIRPS). Conversely, GPI ranked the CPC product the best product for 25 of the stations, followed by PGF and CHRIPS. Integration of CPI and GPI ranking through MCGDM revealed that the CPC was the best precipitation product for the Amu River basin. The performance of PGF was also closely aligned with that of CPC

Assessment of Water Resources Availability in Amu Darya River Basin Using GRACE Data

Water is diminishing in many places of the globe due to human intervention and climate variability. This study was conducted to assess water sustainability in the Amu Darya basin, the largest river catchment of central Asia, using two Gravity Recovery and Climate Experiment (GRACE) satellite solutions with a spatial resolution of 0.5°. Spatial variability of water sustainability was estimated by integrating reliability, resiliency and vulnerability. In addition, the Modified Mann–Kendall (MMK) test was utilized to detect the significant trends in water availability. Findings show a significant decline in the basin’s water supply, especially after 2010. Water availability was more variable in the east and a small area in the south. Trend analysis revealed higher declination in water availability in the range of −0.04 to −0.08 cm/year in the tundra and warm dry continental climate zones and the delta region of the basin ending in the Aral Sea in the cold desert climate zone. Water resources in the cold semi-arid (steppe) and most parts of the cold desert climate are more sustainable than the rest of the basin. Overall, the results indicate that water resources availability in a large-scale basin with climate diversity could be well assessed using the method used in this study

Indonesian kaolin supported nZVI (IK-nZVI) used for the an efficient removal of Pb(II) from aqueous solutions: kinetics, thermodynamics and mechanism

A remarkably efficient Indonesian Kaolin (IK) supported nano zerovalent iron composite (IK-nZVI) has been synthesized, and subjected to the elimination Pb(II) from the wastewater. The results were authenticate the nZVI nanoparticles have a chain shape and establish as separable nanospheres with an average size (29.95 nm) on the surface of IK. The FTIR spectra demonstrate the presence of Al-O as well as Si-O bonds. XRD results demonstrate the presence of zerovalent iron. SEM confirmed less agglomeration of Fe(0) nanoparticles which improves the mechanical strength. The weak signals of Fe and O confirm the establishment of zerovalent iron in nanocomposite. TEM demonstrates that the nanocomposite has a chain like structure. Pb(II)percentage removal was improved by rise in the IK-nZVI amount which results in rising the adsorption site. The nanocomposite had on optimum Pb(II) sorption at pH range of 4.5–6.5. The amount adsorbent increasing with the Pb(II) removal percentage was decreased. Kinetics study demonstrated that Pb(II) sorption was accomplished through more than one processes. IK was proved active support to progress the dispersion, and steadiness of IK-nZVI nanocomposite. The sorption processes pollutant was estimated through the kinetics models, and different sorption isotherm equations like Langmuir (LM), Langmuir-Freundlich (L-F), and Freundlich (FL) isotherms. The IK-nZVI typically accompanies outstanding Pb(II) removal efficiency of 98% and 96.05% with a span of 5 and 10 min for low and high concentrations, respectively. Significantly, the results reveal the maximum adsorption capability of the IK-nZVI is 192.0 mg/g. The thermodynamic study shown endothermic and spontaneous adsorption onto the IK-nZVI surface. Specifically, the IK-nZVI nanocomposite possesses key advantages in terms of simple method, nature friendly, cost-effectiveness, and decent adsorption efficiency for the potential elimination of toxic metal ion (Pb(II)) in the aqueous phase