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Activated Carbon for Wastewater Treatment from Phenol Compounds


Makale | 2022 | Chemistry for Sustainable Development30 ( 3 )

Application of activated carbon (AC) obtained from cotton wastes (bolls, stems, and roots) for phenol adsorp-tion from water, or wastewater dephenolization, is presented. The kinetics of phenol adsorption by carbon adsor-bents were studied using UV/Vis spectrophotometer. The porosity of the formed ACs ranged from 1.952 to 2.339 cm3/g, the volume of macropores was from 1.79 to 2.09 cm3/g, while the commercial sample BAU-A showed 1.920 and 1.320 cm3/g, respectively. The highest phenol adsorption rate, 32.49-52.80 mg/(g center dot min), was observed for contact time up to 5 min on carbon adsorbents obtained from cotton waste. The adsor . . .ption equilibrium was achieved within 5 min after the contact, which is shorter than the analogous commercial adsorbents (7-12 min). Sufficiently high phenol adsorption activity of AC from cotton stems, roots and bolls is revealed. Therefore, the use of AC from cotton wastes as adsorbents for the treatment of industrial wastewater to remove organic and other impurities can be recommended for environmental remediation applications Daha fazlası Daha az

Boron-containing magnetic nanoparticles from Co, Ni, and Fe chloride salts and their catalytic performances on 4-nitrophenol reduction


Makale | 2020 | Inorganic Chemistry Communications116

In this study, magnetic metal nanoparticles (MNP) were prepared by using Fe, Co and Ni ions and NaBH4 as reducing agents in oil-in-water microemulsion system. The prepared MNP were used as catalyst in 4-Nitro phenol (4-NP) reduction to 4-Aminophenol (4-AP). It was found that magnetic Co MNP performed superior catalytic performances than Fe and Ni MNP for 4-NP reduction. The catalytic reduction experiments revealed that as the concentration of reducing agent, NaBH4 that was used in the preparation of Co MNP was increased, the complete conversion time for 4-NP to 4-AP was decreased as the sizes of Co MNP were obatined as 75 /- 16, 60 . . ./- 9, and 37 /- 6 nm when using 0.1, 0.2 and 0.4 M NaBH, respectively. Therefore, Co MNP prepared by using 0.4 M NaBH4 was used in the detailed investigation of various parameters such as the effect Co nanoparticles, reaction temperatures and time. The activation parameters of Co nanoparticle prepared by using 0.4 M NaBH4 as reducing agent was calculated as Ea = 32.1 /- 3.1 kJ mot(-1), Delta H = 28.8 /- 2.2 kJ mot(-1 )and Delta S = - 162.5 /- 9.4 J mol(-1) K-1 that is the best catalytic performance amongst the other Co MNP5. The shelf life (storage) studies of Co nanoparticles showed that smaller Co MNP obtained by using 0.4 M NaBH4 reduce catalytic performance faster than the others, e.g, in the order of Co MNP(0.4 M NaBH4) > Co MNP(0.2 M NaBH4) > Co MNP(0.1 M NaBH4) in 20 day storage at ambient temperature. The activity?f Co MNP was decreased to 58 /- 3?fter five consecutives use while maintaining 100?onversion at every use corroborating the promising industry application of this magnetic Co MNP Daha fazlası Daha az

Renewable-based treatment solution of Reactive Blue 21 dye on fly ash as low-cost and sustainable adsorbent

Mehmet KOBYA

Makale | 2024 | Journal of Chromatography A1715

This study investigated the removal of Reactive Blue 21 (RB 21) dye from aqueous solutions by adsorption, evaluating the waste fly ash (FA). The effects of the parameters, such as initial dye concentration (100–750 mg/L), initial pH (2.0–8.0), adsorbent dose (1.0–4.0 g/L), and temperature (298–323 K) on the adsorption process were investigated. The optimum initial pH value was 2.0 for the highest RB21 dye removal (75.2 mg/g). At optimized conditions (pH 2.0, an adsorbent dosage of 1.0 g/L, a dye concentration of 750 mg/L, and an equilibrium time of 72 h), the highest adsorption capacity was found to be 105.2 mg/g. Moreover, the resu . . .lts of the kinetic studies fitted the pseudo-second-order kinetic model. Equilibrium data were best represented by the Langmuir isotherm model, with a maximum monolayer adsorption capacity of 103.41 mg/g at 323 K. ΔGads0 values were negative and varied from 11.64 to 9.50 kJ/mol in the temperature range of 298–323 K, the values of enthalpy (ΔHadso) and entropy (ΔSadso) of thermodynamics parameters were calculated as 37.62 kJ/mol and 86.67 J/mol K, respectively, indicating that this process was endothermic. Furthermore, the adsorbent costs for powdered activated carbon (PAC) and FA to remove 1 kg of RB 21 dye from aqueous solutions are calculated as 2.52 U.S. and 0.34 U.S. , respectively. It is seen that the cost of FA is approximately 7.4 times lower than PAC. The results showed that FA, a low-cost industrial waste, was promising for the adsorption of RB 21 from aqueous solutions. Keyword: adsorption; fly ash; isotherm; kinetics; reactive blue 2 Daha fazlası Daha az

Urea Uptake and Release by Novel Macrogels from Dimethylacrylamide


Makale | 2019 | Communications in Soil Science and Plant Analysis50 ( 18 )

A novel macrogels poly(N,N-Dimethylacrylamide) (p(DMAAm)) and its derivatives were synthesized from DMAAm for use in urea uptake and release. p(DMAAm) surface was modified by NaOH and HCl to obtain p(DMAAm)/NaOH and p(DMAAm)/HCl, which are negatively and positively charged, respectively. The dynamic swelling behaviors, water retention and pH sensitivities of the macrogels were studied. It was found that all macrogels exhibited the equilibrium swelling ratio (SR) in the range 1068-1451%. Swelling kinetics showed that the macrogels possessed Fickian diffusion behavior while the diffusion coefficient of the macrogels varied from 1.41.1 . . .0(-5) to 2.53.10(-5) cm(2)/min. Furthermore, urea uptake capacity and controlled release properties of the macrogels were studied. The maximum urea uptake capacity at pH 6 for p(DMAAm), p(DMAAm)/HCl, p(DMAAm)/NaOH macrogels were obtained to be 76.7 mg/g, 88.2 mg/g, 110.5 mg/g, respectively. It was concluded that the Langmuir isotherm fits quite well the experimental data. To describe the urea release kinetics, experimental data recorded at different pH solutions were computed through common release models. At pH 8, the p(DMAAm)/NaOH showed the highest release among the three prepared macrogel. Consequently, the results demonstrated that synthesized novel macrogels had high swelling rate and ability of absorbing and releasing of urea at different medium conditions Daha fazlası Daha az

Clinical importance of lipid profile in neonatal calves with sepsis


Makale | 2018 | Journal of the Hellenic Veterinary Medical Society69 ( 4 )

In this study, it was aimed to determine of diagnostic importance of blood lipid levels in neonatal calves with sepsis. The study was carried out on a total of 70 calves, 60 with sepsis and 10 healthy calves. The calves with sepsis were included in the study, according to clinical and hematological findings. The blood samples were taken from the V. jugularis for hematological, lipid profile and biochemical analyzes after the routine clinical examinations of the calves. There were significantly (P < 0.05) decrease in body temperature, increase in respiration rate and capillary refill time in the calves with sepsis compared to control . . . group. The levels of blood urea nitrogen, creatinine concentrations of calves with sepsis were significantly higher (P < 0.05), however, levels of total cholesterol, HDL and LDL concentrations were significantly lower (P < 0.05) than control group. In addition, blood triglyceride and VLDL concentrations of calves with sepsis were higher than control group, however there was no statistical difference. In conclusion, serum total cholesterol, HDL and LDL in neonatal calves with sepsis could be used in evaluation of the sepsis in calves Daha fazlası Daha az

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