In this study, the effectiveness of activated carbon prepared from the
Azolla filiculoides
fern (ACAF) in order to remove ampicillin from aqueous solution was examined. The preparation of the ACAF was performed through chemical and physical activation processes with the presence of ZnCl
2
and at a temperature of 450 °C. The ACAF yield was 44.7% of the fresh
Azolla filiculoides
. The results obtained from the characterization study indicate that the prepared ACAF has excellent surface and internal properties to be used as an adsorbent. The surface area, porosity, and pore volume were estimated to be 716.4 m
2
/g, 51.2%, and 0.621 cm
3
/g, respectively. The functional groups in ACAF that were responsible for the adsorption of ampicillin molecules were detected using FTIR analyses. The maximum efficiency (96.84%) and uptake (114.3 mg/g) of ACAF to remove ampicillin were achieved under the following conditions: ACAF dose = 0.8 g/L, pH = 7, concentration of ampicillin = 100 mg/L, contact time = 60 min, and temperature = 45 °C. It was found that the kinetic and isotherm data matched the pseudo-second-order and Langmuir models with high precision values, respectively. Considering the thermodynamics of the adsorption, the endothermic and spontaneous nature of the ampicillin adsorption onto ACAF was approved. The ampicillin adsorption capacity by ACAF was not significantly affected by the presence of different concentrations of NaNO
3
competitor ion. The considerably higher adsorption capacity of the ACAF for ampicillin (114.3 mg/g) than other previously used adsorbents with excellent regeneration level (five cycles) depicts the superior performance of ACAF in the adsorption systems.
Supplementary Information
The online version contains supplementary material available at 10.1007/s13399-021-01962-4.
Maintaining the water quality is essential because of the limitation of drinking water bodies and their significant effects on life. Recently, much scientific interest has been attracted to the ecological condition assessment of water resources. Because of numerous health issues connected to water quality, the present work aimed to define the water quality status of Chahnimeh reservoirs, Sistan and Baluchistan province, Iran via the Iran Water Quality Index (IRWQISC), the National Sanitation Foundation Water Quality Index (NSFWQI), and human risk assessment. This cross-sectional descriptive work was accomplished in 4 seasons in 2020. The samples were gathered from 5 various points of Chahnimeh reservoirs. This study led to the results that the NSFWQI index was between 29.4 to 49.32, which showed “bad” quality, and the IRWQI index was between 19.27 and 39.23, which indicated “bad” and “relatively bad” quality. The best water quality based on both indexes was observed in the spring, and the worst was in the fall and summer. The highest value of HQ related to nitrate in drinking water was 1.60 in the group of children. However, according to the Monte Carlo simulation, HQ95% was estimated as 1.29. The Sobol sensitivity analysis of the first-order effect showed that daily water’s daily ingestion rate (IR) was the most sensitive input. In addition, the value of the second-order effect indicated that the interaction effect of concentration—ingestion rate was the most sensitive input parameter for HQ. Therefore, regular monitoring is necessary to ensure water safety for human consumption.
This study offers a comprehensive investigation into the efficiency of degradation of acid blue 80 (AB80) dye using a system using ultraviolet (UV) radiation combined with hydrogen peroxide (H2O2) and persulphate (PS) oxidants (UV/PS/H2O2). The degradation reactions were performed under different values of PS and H2O2 concentrations, initial AB80 dye concentration, pH, UV intensity, and contact time. The results revealed that the UV/H2O2 provided the best performance at pH of 5, while the best performance for the UV/PS and UV/PS/H2O2 systems was obtained at pH of 7. Besides, 15 mmol was found to be the optimum concentration for both oxidants. The efficiency of the combined process of the UV/PS/H2O2 was higher than that of the other two processes i.e., UV/PS and UV/H2O2, which was 98.2% for a dye concentration of 25 mg/L. Further, the BOD5/COD ratios at the beginning and end of the UV/PS/H2O2 process were 0.19 and 0.52, respectively, indicative of the conversion of the non-biodegradable dye molecules to biodegradable compounds. The toxicity test was performed using the bioassay method with Daphnia magna, and 90% reduction in toxicity was observed in the effluent. The lethal concentration 50 (LC50) indicator was found to be 4.7 mg/L for the dye solution. The results also revealed that the degradation data followed the pseudo-first-order kinetics, and the reaction rate constant was higher for the UV/PS/H2O2 system than for the other systems. The rate of mineralisation by this process was 0.92. Scavenging studies also showed that both the sulphate (SO°-4) and hydroxyl (OH°) radicals play an important role in the degradation process. Energy consumption in the UV/H2O2, UV/PS, and UV/PS/H2O2 processes was 61, 47.8, and 20.8 kWh/m3, respectively. On conclusion, the UV/PS/H2O2 is an effective and applicable process for the treatment of dye in wastewater, particularly when the medium is neutral.
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