Molecularly Imprinted Polymeric Sorbent for Targeted Dispersive Solid-Phase Microextraction of Fipronil from Milk Samples.

Fipronil, a phenyl pyrazole insecticide, is extensively used in agriculture to control insect infestation. It has the potential to assimilate into the food chain, leading to serious health concerns. We report molecularly imprinted polymer (MIP)-based dispersive solid-phase microextraction for the targeted determination of fipronil in milk samples. Designing such a sorbent is of paramount importance for measuring the accurate amount of fipronil for monitoring its permissible limit. Response surface methodology based on a central composite design following a face-centered approach was used to optimize experimental conditions. The maximum binding capacity of 47 mg g-1 was achieved at optimal parameters of time (18 min), temperature (42 °C), pH (7), and analyte concentration (120 mg L-1). Under these conditions, a high percentage recovery of 94.6 ± 1.90% (n = 9) and a low limit of detection (LOD) and limit of quantitation (LOQ) (5.64 × 10-6 and 1.71 × 10-5 µg mL-1, respectively) were obtained. The MIP was well characterized through a scanning electron microscope (SEM) as well as Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA) methods. Adsorption kinetics of the MIP followed the pseudo-first-order model (R 2 0.99 and χ2 0.96), suggesting the MIP-analyte interaction to be a physiosorptive process, while adsorption isotherms followed the Freundlich model (R 2 0.99). The real sample analysis through high-performance liquid chromatography (HPLC) confirmed the selective determination of fipronil from milk samples.

Greywater reuse: an assessment of the Jordanian experience in rural communities.

Water conservation is a critical issue, particularly in arid countries and countries that suffer a lack of natural water resources. Jordan is one of the most water-scarce countries in the world; this fact has forced the search for alternative sustainable solutions. With the support of several regional and international organizations, tens of projects were implemented across the country over the past 30 years that aimed to reuse greywater in rural communities. The current review provides a wide overview of Jordan's experience in greywater treatment and its reuse for non-potable purposes in rural areas. To the best knowledge of the authors, the present review is the first to assess the Jordanian experience in this field. Many governmental authorities and non-governmental organizations have been involved in Jordan's experience. The greywater reuse systems were established to achieve advantageous environmental and socio-economic consequences on the rural communities. The strategy of greywater treatment was based on a local on-site greywater treatment system in households or the so-called 'autonomous water management'. The applied greywater treatment technologies in households were found efficient in rendering greywater adequate for agricultural uses. However, further improvements and territorial expansion of the experiment are needed.

Adsorption of inorganic mercury from aqueous solutions onto dry biomass of Chlorella vulgaris: kinetic and isotherm study.

This study focused on kinetics and equilibrium isotherms of mercury biosorption from water using dry biomass of Chlorella vulgaris as biosorbent at pH 5.0. Biosorption tests were performed at 2.0 g/L biomass dosage varying initial Hg concentration from 11.0 to 90.6 mg/L. The Lagergren equation was found to best describe the process, with R2 of 0.984 and specific rate constant of 0.029 ± 0.004 min-1. Although equilibrium data were well fitted by the Dubinin and Radushkevich isotherm (R2 = 0.870; qDR = 16.6 mg/g), important insights on phenomenological events occurring at equilibrium were concurrently provided by the Lamgmuir one (R2 = 0.826; q0 = 32.6 mg/g; KL = 0.059 L/mg). FT-IR analysis confirmed that Hg biosorption took place via physisorption. Since C. vulgaris is a fresh-water microalga that can be easily cultivated anywhere, these promising results suggest its possible use as an effective, low-cost biosorbent to treat industrial effluents contaminated by this metal.

Chlorella vulgaris as a lipid source: Cultivation on air and seawater-simulating medium in a helicoidal photobioreactor.

The freshwater microalga Chlorella vulgaris was cultured batchwise on the seawater-simulating Schlösser medium either in a 1.1-L-working volume helicoidal photobioreactor (HeP) or Erlenmeyer flask (EF) as control and continuously supplying air as CO2 source. In these systems, maximum biomass concentration reached 1.65 ± 0.17 g L(-1) and 1.25 ± 0.06 g L(-1) , and maximum cell productivity 197.6 ± 20.4 mg L(-1)  day(-1) and 160.8 ± 12.2 mg L(-1)  day(-1) , respectively. Compared to the Bold's Basal medium, commonly employed to cultivate this microorganism on a bench-scale, the Schlösser medium ensured significant increases in all the growth parameters, namely maximum cell concentration (268% in EF and 126% in HeP), maximum biomass productivity (554% in EF and 72% in HeP), average specific growth rate (67% in EF and 42% in HeP), and maximum specific growth rate (233% in EF and 22% in HeP). The lipid fraction of biomass collected at the end of runs was analyzed in terms of both lipid content and fatty acid profile. It was found that the seawater-simulating medium, despite of a 56-63% reduction of the overall biomass lipid content compared to the Bold's Basal one, led in HeP to significant increases in both the glycerides-to-total lipid ratio and polyunsaturated fatty acid content compared to the other conditions taken as an average. These results as a whole suggest that the HeP configuration could be a successful alternative to the present means to cultivate C. vulgaris as a lipid source. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:279-284, 2016.