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This paper presents the synthesis of visible light-responsive ternary nanocomposites composed of cuprous oxide (Cu 2 O), tungsten trioxide (WO 3), and titanium dioxide (TiO 2) with varying weight percentages (wt.%) of the Cu 2 O. The resulting Cu 2 O/WO 3 /TiO 2 (CWT) nanocomposites exhibited band gap energy ranging from 2.35 to 2.90 eV. Electrochemical and photoelectrochemical (PEC) studies confirmed a reduced recombination rate of photoexcited charge carriers in the CWT nanocomposites, facilitated by a direct Z-scheme heterojunction. The 0.50CWT nanocomposite demonstrated superior photodegradation activity (2.29 × 10−2 min−1) against Reactive Black 5 (RB5) dye under visible light activation. Furthermore, the 0.50CWT nanocomposite exhibited excellent stability with 80.51% RB5 photodegradation retention after five cycles. The 0.50CWT electrode achieved a maximum specific capacitance of 66.32 F/g at 10 mA/g current density, with a capacitance retention of 95.17% after 1000 charge-discharge cycles, affirming its stable and efficient supercapacitor performance. This was supported by well-defined peaks in cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) curves, indicating pseudocapacitive properties. • Direct Z-scheme heterojunction facilitates separation of photoexcited charge carriers. • Photoelectrochemical study proved reduction of charge carriers recombination rate. • Nanocomposite showed excellent chemical and photostability for dye photodegradation. • Chemical oxygen demand test proved complete mineralization of dye by photocatalysis. • High capacitance retention and specific capacitance proved effective supercapacitor. [ABSTRACT FROM AUTHOR]

This research focuses on the synthesis and application of a novel kaolin-supported g-C 3 N 4 /MoO 3 nanocomposite for the degradation of tetracycline, an important antibiotic contaminant in water systems. The nanocomposite was prepared through a facile and environmentally friendly approach, leveraging the adsorption and photocatalytic properties of kaolin, g-C 3 N 4 and MoO 3 nanoparticles, respectively. Comprehensive characterization of the nanocomposite was conducted using techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR) and optical spectra. The surface parameters were studied using N 2 adsorption-desorption isotherm. The elemental composition was studied using X-ray photoelectron spectroscopy. The efficiency of the developed nanocomposite in tetracycline degradation was evaluated and the results revealed an efficient tetracycline degradation exhibiting the synergistic effects of adsorption and photocatalytic degradation in the removal process. The tetracycline degradation was achieved in 60 min. Kinetic studies and thermodynamic analyses provided insights into the degradation mechanism, suggesting potential applications for the nanocomposite in wastewater treatment. Additionally, the recyclability and stability of the nanocomposite were investigated, demonstrating its potential for sustainable and long-term application in water treatment. • Kaolin supported g-C 3 N 4 @MoO 3 ternary nanocomposites have been synthesized for waste water treatment. • The nanocomposites have been characterized by several analytical techniques. • The influence of various parameters in the degradation of tetracycline is explored. • The degradation using Z-scheme unveiling the synergistic effects of adsorption and photocatalytic degradation. [ABSTRACT FROM AUTHOR]

This work investigates the use of novel BiOI@ZIF-8 nanocomposite for the removal of acetaminophen (Ace) from synthetic wastewater. The samples were analyzed using FTIR, XRD, XPS, DRS, PL, FESEM-EDS, and ESR techniques. The effects of the loading capacity of ZIF-8 on the photocatalytic oxidation performance of bismuth oxyiodide (BiOI) were studied. The photocatalytic degradation of Ace was maximized by optimizing pH, reaction time and the amount of photocatalyst. On this basis, the removal mechanisms of the target pollutant by the nanocomposite and its photodegradation pathways were elucidated. Under optimized conditions of 1 g/L of composite, pH 6.8, and 4 h of reaction time, it was found that the BiOI@ZIF-8 (w / w = 1:0.01) nanocomposite exhibited the highest Ace removal (94%), as compared to that of other loading ratios at the same Ace concentration of 25 mg/L. Although this result was encouraging, the treated wastewater still did not satisfy the required statutory of 0.2 mg/L. It is suggested that the further biological processes need to be adopted to complement Ace removal in the samples. To sustain its economic viability for wastewater treatment, the spent composite still could be reused for consecutive five cycles with 82% of regeneration efficiency. Overall, this series of work shows that the nanocomposite was a promising photocatalyst for Ace removal from wastewater samples. • The highest acetaminophen removal by ZIF-8@BiOI photocatalyst was 94% • Optimum condition: 1 g/L of dose; 25 mg/L of Ace; pH 7; 4 h of reaction time • 1O 2 , ·OH and h + were photosensitizers responsible for acetaminophen removal • Spent ZIF-8@BiOI photocatalysts could be regenerated for five consecutive times [ABSTRACT FROM AUTHOR]

Abstract In the present work, one-step green synthesis of WO 3 based on the interaction of ammonium paratungstate and Spondias mombin leaves extract is reported. Different concentrations of iodine and phosphorus in the range of (2%, 5% and 10%) were firstly incorporated into the prepared WO 3 nanoparticles to obtain Iodine doped and Phosphorus doped WO 3 nanoparticles respectively. Subsequently, iodine and phosphorus co-doped WO 3 nanocomposites was prepared using a wet impregnation method followed by calcination at high temperature. The nanomaterials were characterized by HRSEM, HRTEM, BET, UV–Visible, EDS, XRD and XPS. The photo-oxidation of dyeing wastewater by the synthesized WO 3 nanomaterials were tested and assessed using Total organic carbon (TOC) and Chemical oxygen demand (COD) as indicator parameters. XRD and HRSEM analysis demonstrated the formation of only monoclinic phase of WO 3 irrespective of the dopants. The UV–Visible diffuse reflectance spectroscopy showed the band gap energy of 2.61 eV for undoped WO 3 and 2.02 eV for I-P co-doped WO 3 nanocomposites. The surface area of I-P co-doped WO 3 (416.18 m2/g) was higher than the undoped WO 3 (352.49 m2/g). The XPS demonstrated interstitial and substitution of oxygen (O2−) vacancies in WO 3 by I− and P3+ and formed I-P-WO(3-x). The I-P co-doped WO 3 exhibited higher catalytic activities (93.4% TOC, 95.1% COD) than the undoped (54.9% TOC, 79.2% COD) due to the synergistic effects between the two dopants. The experimental data better fitted to pseudo-second order than first order and pseudo-first order model. This study demonstrated the enhanced photocatalytic performance of I-P co-doped WO 3 nanocomposites under sunlight. Highlights • Green synthesis of WO 3 nanoparticles using Spondias mombin aqueous leaves extract. • Mono and co-doping of WO 3 nanoparticles by Iodine and Phosphorus. • Characterization of the nanomaterials and estimation of band gap energy of I-P co-doped WO 3 nanocomposites. • Photocatalytic degradation of Local dyeing wastewater by the prepared nanomaterials under sunlight irradiation. [ABSTRACT FROM AUTHOR]

Abstract Herein, Kiwi peel activated carbon (AC), Materials Institute Lavoisier (MIL-88B (Fe), and AC/MIL-88B (Fe) composite were synthesized and used as catalysts to degrade Reactive Red 198. The material properties were analyzed by the FTIR, BET-BJH, XRD, FESEM, EDX, TGA, and UV–Vis/DRS. The BET surface area of AC, MIL-88B (Fe) and AC/MIL-88B (Fe) was 1113.3, 150.7, and 199.4 m2/g, respectively. The band gap values (E g) estimated by Tauc plot method, were obtained 5.06, 4.19 and 3.79 eV for AC, MIL-88B (Fe) and AC/MIL-88B (Fe), respectively. The results indicated that the AC/MIL-88B (Fe) composite had higher photocatalytic activity (99%) than that of pure AC (79%) and MIL-88B (Fe) catalysts (87%). The decolorization kinetic was matched well with the second-order model. Moreover, the data were modeled using least squares support vector machine which optimized with Cuckoo optimization algorithm. The optimal parameters were found 0.837 and 3.49e+02 based on σ2 and γ values, respectively. The mean square error (MSE) and correlation coefficient (R2) values were obtained 3.97 and 0.948. Therefore, the attained data, materials characterization and prediction of modeling validate the composite form of MIL-88B(Fe) with new AC, had better photocatalytic activity in comparison with the individual form. Graphical abstract Image 1 Highlights • Activated carbon/metal-organic framework nanocomposite photocatalyst was prepared. • Dye degradation mathematical modeling from wastewater was done. • Surface area of AC, MIL-88B and AC/MIL-88B was 1113.3, 150.7, and 199.4 m2/g. • The photocatalytic decolorization kinetics followed the second-order kinetic model. • Least squares support vector machine with Cuckoo algorithm modeled dye degradation. [ABSTRACT FROM AUTHOR]

The present study was done to investigate and compare the photocatalytic and antibacterial activity of two in situ Manganese doped ternary nanocomposites. The dual ternary hybrid systems comprised Mn-doped Ag 2 WO 4 coupled with MoS 2 -GO and Mn-doped MoS 2 coupled with Ag 2 WO 4 -GO. Both hierarchical alternate Mn-doped ternary heterojunctions formed efficient plasmonic catalysts for wastewater treatment. The novel nanocomposites were well-characterized using XRD, FTIR, SEM-EDS, HR-TEM, XPS, UV-VIS DRS, and PL techniques confirming the successful insertion of Mn+2 ions in respective host substrates. The bandgap of the ternary nanocomposites evaluated by the tauc plot showed them visible light-active nanocomposites. The photocatalytic ability of both Mn-doped coupled nanocomposites was investigated against the dye methylene blue. Both ternary nanocomposites showed excellent sunlight harvesting ability for dye degradation in 60 min. The maximum catalytic efficiency of both photocatalysts was obtained at a solution pH value of 8, photocatalyst dose and oxidant dose of 30 mg/100 mL and 1 mM for Mn–Ag 2 WO 4 /MoS 2 -GO, 50 mg/100 mL, 3 mM for Mn–MoS 2 /Ag 2 WO 4 -GO keeping IDC of 10 ppm for all photocatalysts. The nanocomposites showed excellent photocatalytic stability after five successive cycles. The response surface methodology was used as a statistical tool for the evaluation of the photocatalytic response of several interacting parameters for dye degradation by ternary composites. The antibacterial activity was determined by the inactivation of gram-positive (Staphylococcus aureus) and gram-negative (Escherichia coli) bacteria by support-based doped ternary hybrids. [Display omitted] • Alternate Mn-doped ternary heterostructures supported over graphene oxide were prepared hydrothermally. • Mn-doped ternary heterostructures (Mn-M/ AG and Mn-A/ MG) showed 95% and 99% dye degradation. • The effect of alternate Mn doping and synergistic effect of all components of a ternary system was studied. • The antibacterial activity of hybrids was determined against gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. [ABSTRACT FROM AUTHOR]

The occurrence of textile dyeing wastewater discharged into the environment has been recently increasing, resulting in harmful effects on living organisms and human health. The use of green nanoparticles for water decontamination has received much attention. Floral waste can be extracted with the release of natural compounds, which act as reducing and stabilizing agents during the biosynthesis of nanoparticles. Herein, we report the utilization of Chrysanthemum spp. floral waste extract to synthesize green ZnFe 2 O 4 @ZnO (ZFOZx) nanocomposites for the photocatalytic degradation of Congo red under solar light irradiation. The various molar ratio of ZnFe 2 O 4 (0–50%) was incorporated into ZnO nanoparticles. The surface area of green ZFOZx nanocomposites was found to increase (7.41–42.66 m2 g−1) while their band gap energy decreased from 1.98 eV to 1.92 eV. Moreover, the results exhibited the highest Congo red dye degradation efficiency of 94.85% at a concentration of 5.0 mg L−1, and a catalyst dosage of 0.33 g L−1. The • O 2 − reactive species played a vital role in the photocatalytic degradation of Congo red dye. Green ZFOZ3 nanocomposites had good recyclability with at least three cycles, and an excellent stability. The germination results showed that wastewater treated by ZFOZ3 was safe enough for bean seed germination. We expect that this work contributes significantly to developing novel green bio-based nanomaterials for environmental remediation as well as reducing the harm caused by flower wastes. [Display omitted] • Green ZnFe 2 O 4 @ZnO (ZFOZ) nanocomposites were synthesized by green method. • Photodegradation of Congo red was conducted under solar light irradiation. • ZFOZ3 exhibited the highest photocatalytic activity (94.85%). • Green ZFOZ3 was tested with three cycles without significant deconstruction. • The dye solution treated by ZFOZ3 was enough safe to bean seed germination. [ABSTRACT FROM AUTHOR]

Wastewater containing pharmaceutical contaminants has become a critical environmental concern due to rising population and drug consumption caused by increased life expectancy. Diclofenac (DCF) is one of the most applicable drugs for veterinary and human health purposes, polluting surface waters in different ways. This work aims to synthesize a novel pectin-graphene oxide (GO)-magnesium ferrite (MgFe 2 O 4)-zinc oxide (ZnO) nanocomposite (PGMZ) for photocatalytic degradation of DCF in an aquatic environment under visible light irradiation. The single and synthesized nanocomposites were characterized by several analyses, confirming the successful synthesis of the nanocomposite. Effects of four operation conditions, including nanocomposite dosage (1–1.25 g/L), nanocomposite type, initial contaminant concentration (35–55 mg/L), and solution pH (3–11), were investigated on the degradation performance. From the kinetic study, the effect of mixing two composites, i.e., synergy percentage, was 38.7% when ZnO–MgFe 2 O 4 particles were added to the GO-pectin structure. By examining the effect of different free radical enhancers and scavenging compounds on the DCF photodegradation, the most influential scavenging components were in the following order; NaCl > Na 2 CO 3 > Na 2 SO 4 , while K 2 S 2 O 8 was a better enhancer than H 2 O 2 at their optimal concentration. Finally, the PGMZ photocatalyst was reused six times with a reduction of about 20% in its removal efficiency, indicating excellent reusability and stability. [Display omitted] • Pectin-graphene oxide-magnesium ferrite-zinc oxide nanocomposite was prepared for diclofenac degradation. • Based on the kinetic study, synergy percentage was 38.7% by adding ZnO–MgFe 2 O 4 to the pectin-GO. • DCF degradation process is primarily associated with the generation of.•OH radicals. • Pseudo-first-order model fitted the kinetic data well with a high correlation coefficient (>0.99). • Grafting pectin enhanced the catalyst stability with only 21% reduction in degradation rate after six time reusing. [ABSTRACT FROM AUTHOR]

The photocatalytic removal of 2-chlorophenol (2-CP) from water environment was investigated by TiO 2 –RGO–CoO. Cobalt oxide-loaded TiO 2 (TiO 2 –CoO) supported with reduced graphene oxide (RGO) was synthesized using a sol–gel method and then annealed at 500 °C for 5 min. The material characteristics were analyzed by UV–Vis analysis, Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy. Incorporation of cobalt oxide and RGO into the TiO 2 system (TiO 2 –RGO–CoO) lowered the band gap energy to 2.83 eV, which greatly enhanced the visible light absorption. The TiO 2 –RGO–CoO photocatalyst showed complete removal of 20 mg/L 2-CP within 8 h with the addition of 0.01% H 2 O 2 under 100 W visible light irradiation. The photo-degradation efficiency of 2-CP (10 mg/L) was 35.2, 48.9, 58.9 and 98.2% for TiO 2 , TiO 2 –RGO, TiO 2 –CoO and TiO 2 –RGO–CoO, respectively, in the presence of visible light irradiation at solution pH of 6.0. The TiO 2 –RGO–CoO photocatalyst retained its high removal efficiency even after five photocatalytic cycles. [ABSTRACT FROM AUTHOR]

This paper reports on the synthesis, characterization and adsorption properties of a novel nano-composite obtained using the hydrothermal method applied to a fly ash-TiO 2 slurry and hexadecyltrimethyl-ammonium bromide, as surface controlling agent. The new adsorbent was investigated in terms of crystallinity (XRD), surface properties (AFM, SEM, and porosity and BET surface) and surface chemistry (EDX, FTIR). The nanocomposite's properties were sequentially tested in adsorption and photocatalysis processes applied to multi-pollutant synthetic wastewaters loaded with copper cations and two industrial dyes: the acid dye Bemacid Blau and the reactive dye Bemacid Rot; the nano-composite substrate allowed reaching high removal efficiencies, above 90%, both in adsorption and in photodegradation experiments, in optimised conditions. [ABSTRACT FROM AUTHOR]

In the present study, an attempt has been made to design a solar light driven N-rGO-ZnO- CoPc(COOH) 8 nanocomposite for the degradation of cyanide. The morphological and structural characterization of the synthesized nanocomposite was performed by XRD, FT-IR, XPS, UV–vis DRS, FESEM, TEM, EDS, PL spectra and BET surface area. The results revealed that almost 91% degradation and 86% toxicity removal occurred at 25 mgL−1 of initial cyanide concentration by the N-rGO-ZnO-CoPc(COOH) 8 nanocomposite under illumination of solar light within 120 min. Analysis of free radicals reveals that the generation of OH. radicals was the predominant species in the photocatalytic degradation process. The cyanide degradation follows pseudo-first order kinetics. The estimated apparent rate constant (K app) of the above nanocomposite was 3 times higher than that of the ZnO photocatalyst alone together with a very good recycle activities. This might be due to the application of metallpthalocyanine photosensitizer CoPc(COOH) 8 which enhances the rate of visible light absorption efficiency and activates the higher band gap ZnO photocatalyst under visible light. In addition, the presence of residual oxygen in N-rGO also promotes nucleation and anchor sites for interfacial contact between ZnO and N-rGO for effective charge transfer. Further, the N-rGO-ZnO-CoPc(COOH) 8 photocatalytic system showed significant antibacterial activities against mixed culture systems. Therefore, the N-rGO-ZnO-CoPc(COOH) 8 nanocomposite may be an alternative solar light driven photocatalyst system for the removal of cyanide from the wastewater along with its strong disinfectant activities. [Display omitted] • A novel N-rGO-ZnO-CoPc(COOH) 8 p-n junction nanocomposite was synthesized. • 3D rectangular nanoplaque CoPc(COOH) 8 photosensitizer enhances visible light absorption. • Cyanide degradation mechanism, kinetics and toxicity removal have been evaluated. • The N-rGO-ZnO-CoPc(COOH) 8 nanocomposite shown a strong antibacterial properties. [ABSTRACT FROM AUTHOR]

Herein, a green and facile methodology was used for the structural design of semiconductor nanomaterials and employed as efficient photocatalyst to resolve the environmental issues of water pollutants. Titanium oxide coupled with bismuth oxide (TiO 2 @Bi 2 O 3) nanocomposite was synthesized by employing the seed extract of Sapindus mukorossi (commonly found plant in India) and subsequently used for the elimination of toxic, and persistence industrial pollutants namely bisphenol A (BPA) and methylene blue (MB). Microscopic and spectroscopic techniques revealed particle size of synthesized nanocomposite found less than 50 nm along with high crystallinity. Appearance of stretching vibrations at 459 cm−1 for Bi–O–Ti in the IR spectra of nanocomposite has established the coupling of TiO 2 with Bi 2 O 3. The parameters of degradation were optimized by varying the pollutant concentration, catalytic amount and pH in the presence of natural sunlight. The nanocomposite TiO 2 @Bi 2 O 3 showed maximum degradation (MB: 94% and BPA: 91%) at a minimum concentration of pollutant (50 mgL−1) with catalyst amount (35 mg), neutral pH and reduces half-life of pollutants (BPA: 1h, MB: 0.5h). Owing of higher surface area (80 m2g-1), lower band gap (2.5 eV), and more negative zeta potential value (−40.3 mV) results into excellent photocatalytic properties. The breakage of S–N conjugated system in MB results into rapid degradation as compare to BPA. The degradation followed first-order kinetics and Langmuir adsorption in both the cases. Presence of active radicals during the photocatalysis process was responsible for quick degradation and strongly supported by scavenger analysis. GC-MS analysis revealed the degradation of toxic pollutants into safer metabolites and finally mineralized. Multiple times (n = 8) reusability of green photocatalyst advocated sustainability and appropriate for industrial applications. [Display omitted] • Natural extract based synthesis of TiO 2 @Bi 2 O 3 nanocomposite. • First-order degradation of Bisphenol A (91%) and Methylene Blue (MB) dye(9 4%) by TiO 2 @Bi 2 O 3. • Optimization of concentration, pH, catalyst dose and source of irradiation. • Hybrid nanostructure increased charge separation and prevent e−/h + recombination behavior. • Small non-toxic by-products and excellent reusability (8th cycle) confirm high efficiency. [ABSTRACT FROM AUTHOR]

Contamination of surrounding waters with antibiotics by aquaculture effluents can be problematic due to the possible increase of bacterial resistance, making it crucial the efficient treatment of those effluents before their release into the environment. In this work, the application of waste-based magnetic biochar/titanium dioxide (BC/TiO 2) composite materials on the photodegradation of two antibiotics widely used in aquaculture (sulfadiazine (SDZ) and oxolinic acid (OXA)) was assessed. Four materials were synthesized: BCMag (magnetized BC), BCMag_TiO 2 (BCMag functionalized with TiO 2), BC_TiO 2 _MagIn and BC_TiO 2 _MagEx (BC functionalized with TiO 2 and afterwards magnetized by in-situ and ex-situ approaches, respectively). SDZ half-life time (t 1/2) noticeably decreased 3.9 and 3.4 times in presence of BCMag_TiO 2 and BC_TiO 2 _MagEx, respectively. In the case of OXA, even though differences were not so substantial, the produced photocatalysts also allowed for a decrease in t 1/2 (2.6 and 1.7 times, in presence of BCMag_TiO 2 and BC_TiO 2 _MagEx, respectively). Overall, the here synthesized BC/TiO 2 magnetic nanocomposites through a circular economy process are promising photocatalysts for a sustainable solar-driven removal of antibiotics from aquaculture effluents. [Display omitted] • Novel waste-based magnetic biochar/titanium dioxide composite materials were produced. • SDZ t 1/2 decreased from 11.2 ± 0.5 h (no catalyst) to 2.9 ± 0.1 h (presence of BCMag_TiO 2). • OXA t 1/2 decreased from 1.21 ± 0.08 h (no catalyst) to 0.46 ± 0.01 (presence of BCMag_TiO 2). • A considerable SDZ mineralization was achieved using BCMag_TiO 2 (70 ± 2%, after 32 h). • After 32 h and in presence of BCMag_TiO 2 , OXA mineralization was 65 ± 1%. [ABSTRACT FROM AUTHOR]

In the last decades, the use of magnetic nanocomposites as a catalyst was considered for removal of organic pollutants due to its easy separation. Therefore, initially, TiO 2 @ZnFe 2 O 4 /Pd nanocomposite was prepared and then used in the photodegradation of diclofenac under direct solar irradiation in the batch and continuous systems. The structure, morphology and other specifications of produced nanocatalyst were determined via XRD, VSM, FESEM/EDX, FTIR, GTA, UV–Vis, Zeta potential, XPS and ICP-OES. The effective factors on diclofenac removal via nanophotocatalyst viz. pH, catalyst concentration, initial concentration of diclofenac, and flow rate and column length on diclofenac photodegradation were studied. Based on the results, the optimal rate for pH, catalyst concentration, and initial concentration of diclofenac was 4, 0.03 g/l and 10 mg/l respectively. Pd-coated TiO 2 @ZnFe 2 O 4 magnetic photocatalyst had higher photocatalytic activity in diclofenac photodegradation in relation to ZnFe 2 O 4 and TiO 2 @ZnFe 2 O 4 under solar light irradiation. The findings showed that after five recycles, the photocatalytic efficiency did not show much reduction i.e. the removal efficiency from 86.1% in the first cycle reduced only to 71.38% in the last cycle. Likewise, in this study, with flow rate reduction and column length increase diclofenac degradation rate increased. Image 1 • TiO 2 @ZnFe 2 O 4 /Pd nanocomposite was prepared using the photodeposition method. • Distributed Pd nanoparticles on TiO 2 significantly increased its photocatalytic activity. • DCF degradation rate was increased by flow rate reduction and column length increase. • TiO 2 @ZnFe 2 O 4 /Pd is highly efficient up to 5 cycles of magnetic separation and recovery. [ABSTRACT FROM AUTHOR]

A simple biogenic approach for synthesis of Fe 3 O 4 /Au nanocomposite with 31 nm size using aqueous extract of Carum carvi L. seeds has been reported. Phytochemicals of Carum carvi L. seeds extract play three roles, including reducing, capping, and stabilizing agents during the nanocomposite fabrication process. Resulting nanocomposite was characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, differential reflectance spectroscopy, vibrating-sample magnetometer, energy-dispersive X-ray spectroscopy and X-ray elemental mapping. Differential reflectance spectroscopy investigated optical property and absorption spectra display a sharp absorption agreeing to a bandgap of 1.6 eV. Photocatalytic activity of biogenic Fe 3 O 4 /Au nanocomposite has been investigated for degradation of imatinib and imipenem drugs under UV and visible light irradiation, due to pharmaceuticals have shown to be recalcitrant in wastewater and conventional wastewater treatments do not remove them, often. Degradation efficiency of imatinib, and imipenem are about 92% and 96% after 1200 s exposure UV light and about 82% and 84% after 3600s exposure visible light in the concentration of 10 ppm drugs. Also, antimicrobial activity of biogenic Fe 3 O 4 /Au nanocomposite was investigated on three human pathogens and best result can see in 25 mg/mL of nanocomposite versuse Bacillus subtilis that inhibition zone is about 27 mm. Design of nanocomposites capable of simultaneously removing pharmaceutical and microbial contaminations is important in environments such as hospitals wastewater treatment. • Biogenic Fe 3 O 4 /Au nanocomposite photocatalyst prepared at room temperature. • Nanocomposite showed excellent photocatalyst activity in UV and Visible light. • Photocatalytic mechanism of biogenic Fe 3 O 4 /Au nanocomposite proposed. • Biogenic Fe 3 O 4 /Au nanocomposite showed superior antimicrobial activity. [ABSTRACT FROM AUTHOR]