“…Optimum % photo-removal efficiency of 90.2% for CAP and 92.74% reduction in the COD value (from initial value of 494.33 ± 0.69 mg/L to 35.91 ± 0.18 mg/L) were obtained upon the treatment of the effluent with rGO-ZnO nanocomposite thereby affirming its excellent photocatalytic degradation efficiency under prevailing conditions. The result of this work is comparable to previous studies on treatment of effluents using different photocatalyst adsorbents 3 , 36 .…”
Section: Resultssupporting
confidence: 89%
“…The BJH cumulative pore volume was calculated to be about 0.4 cc/g. The result of this study revealed a much improved surface area and narrower pore size than previous works involving ZnO nanoparticles alone 3 , 31 . Figure 6 Nitrogen adsorption/desorption isotherm ( a ), BJH pore size distribution ( b ).…”
Section: Resultsmentioning
confidence: 41%
“…This diffraction pattern agreed with the standard JCPDS card No. 00-036-1451 data and other previous studies for ZnO nanoparticles 3 , 29 , 30 . The average crystallite size of the nanocomposite was calculated using the Debye–Scherrer Eq.…”
Section: Resultsmentioning
confidence: 65%
“…Advanced oxidation processes such as semiconductor-based homogenous/heterogenous photocatalysis, sonocatalysis, fenton, electrochemical oxidation, ozonation, etc. have gained enormous attention over the last few decades for the treatment of pharmaceutical and agricultural effluents due to their numerous advantages including cost effectiveness, time and ability to degrade organic and inorganic pollutants to less toxic substances 3 – 7 . Semiconductors such as cadmium sulfide (CdS), zinc sulfide (ZnS), ferric oxide (Fe 2 O 3 ), titanium oxide (TiO 2 ) and zinc oxide (ZnO) nanoparticles can function as a sensitizer for light reduced redox reactions via the generation of reactive oxidative species including hydroxyl radicals, hydrogen peroxide and superoxide anions 8 .…”
Improper discharge of waste dry cell batteries and untreated antibiotics laden effluents to the environment pose serious threat to the sustenance of the ecosystem. In this study, synthesis of reduced graphene oxide-ZnO (rGO-ZnO) nanocomposite was achieved via a bioreduction process using waste dry cell battery rod as graphene oxide (GO) precursor. The nanocomposite was applied in the ultraviolet photocatalytic degradation of chloramphenicol (CAP) at 290 nm in the presence of hydrogen peroxide. RGO-ZnO nanocomposite was characterized by SEM, TEM, XRD, BET and FTIR. TEM image of the nanocomposite revealed a polydispersed, quasi-spherical zinc oxide on a coarse reduced graphene oxide surface. XRD patterns showed sharp, prominent crystalline wurtzite hexagonal phases of ZnO and rGO. BET surface area of the nanocomposite was 722 m2/g with pore size of 2 nm and pore volume of 0.4 cc/g. % photo-removal efficiency increased with increasing irradiation time but diminished at higher pH, temperature and CAP concentration. Photocatalytic adsorption process fitted more accurately into the Freundlich model (R2 = 0.99) indicating a multilayer adsorption mechanism. 92.74% reduction in chemical oxygen demand (COD) level of veterinary effluent was obtained after treatment with the nanocomposite thus affirming its effectiveness in real waste water samples.
“…Optimum % photo-removal efficiency of 90.2% for CAP and 92.74% reduction in the COD value (from initial value of 494.33 ± 0.69 mg/L to 35.91 ± 0.18 mg/L) were obtained upon the treatment of the effluent with rGO-ZnO nanocomposite thereby affirming its excellent photocatalytic degradation efficiency under prevailing conditions. The result of this work is comparable to previous studies on treatment of effluents using different photocatalyst adsorbents 3 , 36 .…”
Section: Resultssupporting
confidence: 89%
“…The BJH cumulative pore volume was calculated to be about 0.4 cc/g. The result of this study revealed a much improved surface area and narrower pore size than previous works involving ZnO nanoparticles alone 3 , 31 . Figure 6 Nitrogen adsorption/desorption isotherm ( a ), BJH pore size distribution ( b ).…”
Section: Resultsmentioning
confidence: 41%
“…This diffraction pattern agreed with the standard JCPDS card No. 00-036-1451 data and other previous studies for ZnO nanoparticles 3 , 29 , 30 . The average crystallite size of the nanocomposite was calculated using the Debye–Scherrer Eq.…”
Section: Resultsmentioning
confidence: 65%
“…Advanced oxidation processes such as semiconductor-based homogenous/heterogenous photocatalysis, sonocatalysis, fenton, electrochemical oxidation, ozonation, etc. have gained enormous attention over the last few decades for the treatment of pharmaceutical and agricultural effluents due to their numerous advantages including cost effectiveness, time and ability to degrade organic and inorganic pollutants to less toxic substances 3 – 7 . Semiconductors such as cadmium sulfide (CdS), zinc sulfide (ZnS), ferric oxide (Fe 2 O 3 ), titanium oxide (TiO 2 ) and zinc oxide (ZnO) nanoparticles can function as a sensitizer for light reduced redox reactions via the generation of reactive oxidative species including hydroxyl radicals, hydrogen peroxide and superoxide anions 8 .…”
Improper discharge of waste dry cell batteries and untreated antibiotics laden effluents to the environment pose serious threat to the sustenance of the ecosystem. In this study, synthesis of reduced graphene oxide-ZnO (rGO-ZnO) nanocomposite was achieved via a bioreduction process using waste dry cell battery rod as graphene oxide (GO) precursor. The nanocomposite was applied in the ultraviolet photocatalytic degradation of chloramphenicol (CAP) at 290 nm in the presence of hydrogen peroxide. RGO-ZnO nanocomposite was characterized by SEM, TEM, XRD, BET and FTIR. TEM image of the nanocomposite revealed a polydispersed, quasi-spherical zinc oxide on a coarse reduced graphene oxide surface. XRD patterns showed sharp, prominent crystalline wurtzite hexagonal phases of ZnO and rGO. BET surface area of the nanocomposite was 722 m2/g with pore size of 2 nm and pore volume of 0.4 cc/g. % photo-removal efficiency increased with increasing irradiation time but diminished at higher pH, temperature and CAP concentration. Photocatalytic adsorption process fitted more accurately into the Freundlich model (R2 = 0.99) indicating a multilayer adsorption mechanism. 92.74% reduction in chemical oxygen demand (COD) level of veterinary effluent was obtained after treatment with the nanocomposite thus affirming its effectiveness in real waste water samples.
“…The method by Ayanda et al [18] was used in the synthesis of zinc oxide nanoparticles (Fig. 1) and to prepare the composite, 0.5 g of zinc oxide nanoparticles was mixed thoroughly with 5 g of the acha chaff before the material was air and oven dried at 100 °C.…”
Section: Preparation Of Nano Zinc Oxide/acha Waste Compositementioning
The presence of emerging pollutants like pharmaceutical compounds in the environment is currently an issue of concern. Pharmaceutical compounds often escape conventional treatment systems and are persistent in the receiving environment; thus, the advanced oxidation processes could complement existing treatment methods to completely remove pharmaceuticals from contaminated water bodies. This work investigated the removal of metronidazole by ultra-violet light catalyzed by zinc oxide nanoparticles supported on acha waste. The synthesized zinc oxide nanoparticles, acha waste, and zinc oxide nanoparticles/acha waste composite were characterized by electron microscopy (SEM and TEM), Fourier transforms infrared spectrometry (FTIR) and X-ray diffractometry (XRD). Experimental results revealed that the UV light combined with zinc oxide nanoparticles and/or acha waste was more effective for metronidazole removal in combination than UV alone. The degradation of the metronidazole by UV light only, UV/nano-ZnO, and UV/nano-ZnO/acha waste systems follow the pseudo-first-order kinetic model. The addition of a catalyst to the UV reactor enhanced the degradation of metronidazole (5 mg/L) from 41.0 up to 86.1%. The outcome of this research showed that UV light in the presence of nanometal oxides and composites is an efficient technique for the removal of pharmaceuticals from an aqueous solution.
Amoxicillin (AMX) is an antibiotic commonly used to treat bacterial and respiratory diseases in humans and animals. In this study, magnetically imprinted polymers (MMIPs) were successfully synthesized and characterized by the surface imprinting method to selectively separate AMX from an aqueous medium. The suitability of kinetic models and isothermal models for the adsorption of AMX from aqueous solutions using magnetic polymers was compared with an unprinted reference polymer (MNIP). The obtained data showed that the adsorption process is compatible with the pseudo‐second order kinetic model and Langmuir isotherm. In addition, adsorption selectivity experiments were performed and it was found that the MMIPs exhibited excellent selective adsorption capacity for AMX. The MMIPs possessed an adsorption capacity of 134 mg/g for AMX and the imprinting factor was 2.23. The MMIPs were also recyclable and retained 86 % of their adsorption capacity after 7 cycles. Based on these results, the study provides a sustainable option in terms of high added value, environmentally friendly, flexible, safe, energy efficient and cost effective in terms of effective removal of pollutants and recycling of adsorbents.
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