This study aimed to develop magnetic Fe3O4/sugarcane bagasse activated carbon composite for the adsorption of arsenic (III) from aqueous solutions. Activated carbon (AC) was prepared from sugarcane bagasse by chemical activation using H3PO4 as an activating agent at 400 °C. To enhance adsorption capacity for arsenic, the resultant AC was composited with Fe3O4 particles by facile one-pot hydrothermal treatment. This method involves mixing the AC with aqueous solution of iron (II) chloride tetrahydrate, polyvinyl pyrrolidone (PVP), and ethanol. Batch adsorption experiments were conducted for the adsorption of As (III) onto the composite. The effects of pH, adsorbent dosage, and contact time on the arsenic adsorption were studied. The result showed that the composite could remove the arsenic from the water far more effectively than the plain AC. The highest percentage of arsenic removal was found at pH at 8, adsorbent dose of 1.8 g/L, and contact time of 60 min. Langmuir and Freundlich adsorption isotherm was used to analyze the equilibrium experimental data. Langmuir model showed the best fit compared to the Freundlich model with a maximal capacity of 6.69 mg/g. These findings indicated that magnetic Fe3O4/sugarcane bagasse AC composite could be potentially applied for adsorptive removal of arsenic (III) from aqueous solutions.

Nitrogen fixation is crucial for plants as it is utilized for the biosynthesis of almost all biomolecules. Most of our atmosphere consists of nitrogen, but plants cannot straightforwardly assimilate this from the air, and natural nitrogen fixation is inadequate to meet the extreme necessities of global nutrition. In this study, nitrogen fixation in water was achieved by an AC-driven non-thermal atmospheric pressure nitrogen plasma jet. In addition, Mg, Al, or Zn was immersed in the water, which neutralized the plasma-treated water and increased the rate of nitrogen reduction to ammonia due to the additional hydrogen generated by the reaction between the plasma-generated acid and metal. The effect of the plasma-activated water, with and without metal ions, on germination and growth in corn plants (Zea Mays) was investigated. The germination rate was found to be higher with plasma-treated water and more efficient in the presence of metal ions. Stem lengths and germination rates were significantly increased with respect to those produced by DI water irrigation. The plants responded to the abundance of nitrogen by producing intensely green leaves because of their increased chlorophyll and protein contents. Based on this report, non-thermal plasma reactors could be used to substantially enhance seed germination and seedling growth.

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In this article, we developed a dual-band band-pass filter (DB-BPF) based on stepped impedance resonators (SIRs) using coupled feeding lines input and output ports. The developed filter allows the adjustment of the frequency and the bandwidth of the upper band (3.8 GHz) and the lower band (2.4 GHz). The transmission coefficients of the DB-BPF are improved by maximizing the coupling between the SIRs. Furthermore, the capability of the rejection band is increased and the insertion losses between the two pass-bands are reduced. The experimental results for the insertion loss (S 21 ) and the return loss (S 11 ) of the lower band (2.4 GHz) were1.0 and 2.0 dB, respectively while the insertion loss and return loss for the upper band (3.8 GHz) were 23 and 25 dB, respectively. The 3 dB fractional bandwidths obtained for both bands were about 200 MHz and four transmission zeros around the passband edges were created to improve the selectivity of the DB-BPF. The overall size of the DB-BPF was also reduced significantly.

This article describes the development of an optimized microstrip wideband bandstop filter (BSF) with open stubs for ultrawideband applications. Simulated results agree with the measured results, demonstrating in the experimental results a 10 dB bandwidth from 4.6 to 7.6 GHz, insertion loss (S21) of −33.9 dB, and minimum return loss (S11) of −0.40 dB at 6.1 GHz. Additionally, an equivalent circuit of the wideband BSF is built to estimate the electromagnetic simulation results for practical realization. The features of the design have a reduced size, wideband rejection, higher insertion loss, and tunable bandwidth, which can be performed by adjusting the L‐shaped stubs (0.41λg and 0.29λg) toward the 50 Ω input and output ports. The designed BSF occupied the size of 0.35λg × 0.29λg. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1003–1006, 2015