Removal of Nitrate from Aqueous Solutions by Starch Stabilized nano Zero-Valent Iron(nZVI)

Background and Objective: Nitrate is one of the inorganic anions derived as a result of oxidation of elemental nitrogen. Urban and industrial wastewater, animal and vegetable waste products in large cities that have organic nitrogen are excreted along the soil. The primary risk of Nitrate in drinking water occurs when nitrate in the gastrointestinal tract switch to nitrite. Nitrite causes the oxidation of iron in hemoglobin of red blood cells, result in red blood cells could not carry the oxygen, a condition called methemoglobinemia. Therefore, achieving the new technologies for nitrate removal is necessary. Material and Methods: The present study was conducted at laboratory Scale in non-continuous batches. Stabilized adsorbent was produced through reducing Iron sulfate by sodium borohydride (NaBH4) in presence of Starch (0.2W %) as a stabilizer. At first, the effect of various parameters such as contact time (10-90min), pH (3-11), adsorbent dose (0.5-3 g/L) and initial concentration of arsenate (50-250 mg/L) were investigated on process efficiency. Freundlich and Langmuir isotherm model equilibrium constant, were calculated. Residual nitrate were measured by using the DR5000 spectrophotometer. Results: The optimum values based on RSM for pH, absorbent dose, contact time, and initial concentration of nitrate were 5.87, 2.25 g/L, 55.7 min, and 110.35 mg/L respectively. Langmuir isotherm with R2= 0.9932 for nitrate was the best graph for the experimental data. The maximum amount of nitrate adsorption was 138.88mg/g. Conclusion: Stabilized absorbent due to have numerous absorption sites and Fe0 as a reducing agent could have great potential in nitrate removal from water

Adsorptive Removal of Arsenic and Mercury from Aqueous Solutions by Eucalyptus Leaves

The study is a first-time investigation into the use of Eucalyptus leaves as a low-cost herbal adsorbent for the removal of arsenic (As) and mercury (Hg) from aqueous solutions. The adsorption capacity and efficiency were studied under various operating conditions within the framework of response surface methodology (RSM) by implementing a four-factor, five-level Box–Wilson central composite design (CCD). A pH range of 3–9, contact time (t) of 5–90 min, initial heavy metal (As or Hg) concentration (C 0) of 0.5–3.875 mg/L, and adsorbent dose (m) of 0.5–2.5 g/L were studied for the optimization and modeling of the process. The adsorption mechanism and the relevant characteristic parameters were investigated by four two-parameter (Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich) isotherm models and four kinetic models (Lagergren’s pseudo-first order (PFO), Ho and McKay’s pseudo-second order (PSO), Weber–Morris intraparticle diffusion, and modified Freundlich). The new nonlinear regression-based empirical equations, which were derived within the scope of the study, showed that it might be possible to obtain a removal efficiency for As and Hg above 94% at the optimum conditions of the present process-related variables (pH = 6.0, t = 47.5 min, C 0 = 2.75 mg/L, and m = 1.5 mg/L). Based on the Langmuir isotherm model, the maximum adsorption or uptake capacity of As and Hg was determined as 84.03 and 129.87 mg/g, respectively. The results of the kinetic modeling indicated that the adsorption kinetics of As and Hg were very well described by Lagergren’s PFO kinetic model (R 2 = 0.978) and the modified Freundlich kinetic model (R 2 = 0.984), respectively. The findings of this study clearly concluded that the Persian Eucalyptus leaves demonstrated a higher performance compared to several other reported adsorbents used for the removal of heavy metals from the aqueous environment.Funding Information The authors would like to thank Tehran University of Medical Sciences for financial support.Scopu

Data on quality indices of groundwater resource for agricultural use in the Jolfa, East Azerbaijan, Iran

The aim of this study was to evaluate the groundwater quality Indices of Groundwater resource for Agricultural Use in jolfa city (Iran) during one decade (2003–2013). Data showed in the first and end year of the study period, the Mean±SD of Sodium Adsorption Ratio (SAR) and Sodium Percentage (Na%) indices 5455.77±3878.02, 3638.69±3565.19 and 51.49±15.65, 41.58±17.69, respectively. The data indicate that the, in terms of sodium percentage and sodium adsorption ratio, the water quality in this area is not suitable for irrigation. Keywords: Groundwater, Indices changes, SAR, Na%, Jolf