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Significant efforts are being made to produce biofuels to replace fossil fuels and address the issues caused by global climate change. Due to its potential better conversion efficiency to useable power, decreased emission of pollutants, and high energy density, H 2 is one of the prospective options that are seen as a desirable future clean energy carrier. Although there are numerous technologies available for producing H 2 , this review concentrates on fermentative H 2 production techniques, their drawbacks, and current developments. While being a promising method, fermentative strategies still have several drawbacks, including low H 2 production yields. Many approaches have been used to address these issues; among them, the field of metabolic pathway engineering has made enormous strides. To improve H 2 generation, this paper reviewed and discussed several metabolic pathways and modified strains. As well as the challenges involved in H 2 scale-up from a laboratory setting to a commercial scale. • Biohydrogen production via fermentative methods is reviewed and elaborated. • Metabolic engineering methods are proposed for scaling up fermentative biohydrogen. • Challenges of fermentative biohydrogen production and potential solutions. • Bionanotechnology and modified strains enhanced biohydrogen production. [ABSTRACT FROM AUTHOR]

In this study, two-step simple method was employed to synthesize new oligomers with significant antibacterial activity. The interaction of ethylenediamine with epichlorohydrin produced ethylenediamine-epichlorohydrin oligomer (EEO), which is subsequently modified by 2,4,5-trichlorophenol to generate ethylenediamine-epichlorohydrin-trichlorophenol oligomer (EETO). Infrared spectroscopy, nuclear magnetic resonance spectroscopy, scanning electron microscopy, and thermogravimetric analyses were used to characterize the oligomers. The amine group and C –Cl peak in the EEO and EETO spectra were both validated by the characterization data, respectively. EEO showed substantial antibacterial activity against S. aureus (1 × 107, 1 × 105, and 1 × 103 CFU/mL) with a minimal inhibition concentration (MIC) of 1250 g/mL at all concentrations. With the same concentrations, EETO demonstrated 156, 39, and 9.77 g/mL, respectively. Furthermore, in a well diffusion assay with the same microorganisms, EEO and EETO had diameters of 20 and 30 mm. Furthermore, stem cells were used to conduct a cytotoxicity test on EETO, which revealed that the compound is harmless to cells up to 10 g/mL. Both oligomers are promising antibacterial materials for liquid toilet cleaners or hospital disinfectants due to their water-soluble nature. [ABSTRACT FROM AUTHOR]

The ability of electrocoagulation (EC) to treat water and wastewater effectively is well-known. There are several improvements that have been adopted in EC processes to enhance treatability, performance, or reduce environmental impacts. Such improvements include: addition of air and hydrogen peroxide to generate radicals; use of an air cathode to reduce energy consumption; polarity reversal for reducing electrode passivation; and use of renewable energy generation as the source of electrical energy. Each of these improvements exploits different mechanisms to improve the applicability of EC. There are several emerging applications where EC has been shown to be suitable, including microplastics, nanoparticles, emerging contaminants, oil and grease, and disinfection. [ABSTRACT FROM AUTHOR]

Conventional methods are inefficient to treat water contaminated with persistent organic contaminants. To decontaminate bacteria and 2,4,5‐trichlorophenol (TCP) contaminated water, a heterogeneous photocatalysis‐based advanced oxidation process was applied in this study. A Li‐doped ternary Zn0.5Ni0.5Fe2O4 (ZNF) photocatalyst (Li/ZNF) was synthesized via a facile co‐precipitation technique and characterized. The Li/ZNF has a sufficient specific surface area (69.8 m2.g−1), and an appropriate bandgap of 2.89 eV. Under optimal conditions, 10 mg of Li/ZNF photocatalyst degraded 80 % of 50 mg L−1 TCP in 6 h at pH 3 in the presence of 4 mM H2O2. After use, the Li/ZNF photocatalyst was magnetically separated and reused numerous times, with an efficiency of 66 % after the fifth reuse cycle. In the antibacterial time‐kill assay, 15 and 25 mg of Li/ZNF inhibited 1×107 CFU.mL−1 of S. Aureus and E. coli bacteria after 60 min of UV exposure, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] • Calcined CaFe–LDH based hybrid photocatalyst was successfully prepared. • 1.0 g CuCr 2 O 4 @CaFe–LDO achieved 66% COD removal after 300 mins in the dark. • CuCr 2 O 4 @CaFe–LDO/K 2 S 2 O 8 /sunlight system resulted in ~99% and 98.3% COD and colour removal. • Seven phenolic compounds were found in the crude olive mill wastewater and were completely degraded after 300 min. • The catalyst was recovered easily with an external magnet from the bulk solution after the reaction. Wastewater from the olive mill constitutes a serious environmental concern, as it is characterized by a high inorganic and organic load. Here, a hybrid photocatalyst based on calcined Ca-Fe–LDH was successfully synthesized for the degradation of phenolic compounds and the removal of chemical oxygen demand (COD) from the high-strength olive mill wastewater (OMW). The catalyst (CuCr 2 O 4 @CaFe–LDO) displayed a stable ~4.48 µA cm−2 photocurrent response, a 2.56 eV bandgap and a wide variety of pores with an average size of 12.51 nm. 1.0 g CuCr 2 O 4 @CaFe–LDO achieved 66% COD removal after 300 mins without an oxidant in the dark, while after 180 mins of reaction, CuCr 2 O 4 @CaFe–LDO/K 2 S 2 O 8 /sunlight system resulted in ~99% and 98.3% COD and colour removal. Seven phenolic compounds were found in the crude OMW, with hydroxytyrosol (76.84%) and tyrosol (15.14%) being the main ones. The final pH of the sample treated increased from 4.3 to 7.3, which confirmed the degradation of phenolics and fatty acids in the OMW. OH, SO 4 −, h+ and O 2 − contributed notably to the degradation of polyphenols and the spent catalyst was easily and rapidly recovered from the bulk solution due to its saturation magnetization of 54.7 emu g−1. [ABSTRACT FROM AUTHOR]

With the growing concern of biofilm-associated infections and drug-resistant bacteria, an increasing interest in developing novel antibacterial agents is an urgent priority. Metal oxide-based polymeric materials are able to distinguish mammalian cells from bacterial cells and thus provide long-term antibacterial growth inhibition. Herein, we report the preparation of MgO, NiO and chitosan-coated metal oxide (CS–MO) nanocomposites via a simple in situ chemistry approach. Fourier transform infrared spectroscopy, X-ray diffraction patterns and X-ray photoelectron spectra results proved the formation of CS–MgO and CS–NiO nanocomposites. Also, the particle sizes were observed to be 18.3 and 25.5 nm for CS–NiO and CS–MgO, respectively. All the samples exhibited antibacterial activities against the Escherichia coli and Staphylococcus aureus strains; however, more effective against S. aureus compared to E. coli. Noticeably, 5 μg/mL CS–NiO comparatively exhibited highest bactericidal capability where E. coli and S. aureus viabilities were reduced to 25–47% after 12 h incubation. After treatment with 15 μg/mL of CS–NiO, ∼98% of S. aureus and 92.3% of E. coli cells were inhibited. [ABSTRACT FROM AUTHOR]

Pyrochar–AgBr (DCG–AgBr) produced from discarded chewing gum for the decontamination of trichlorophenol (2,4,5-TCP) is reported. The DCG–AgBr specific surface area (249.5 m2/g), the pore volume of 0.998 cm3/g, surface functional groups and thermal analysis were established. The 2,4,5-TCP removal efficiency at 10 mg/L was estimated to be ∼96% and the dynamic behavior was successfully described by the Thomas and Yoon–Nelson models. Based on the economic analysis, the total cost for treatment of 2,4,5-TCP simulated wastewater was 14.39 US$/m3. For the first time, commonly discarded chewing gum was employed as a precursor for fabrication of adsorbents for wastewater treatment. [ABSTRACT FROM AUTHOR]

• Through green synthesis, a new bimetallic licu-ferrite nanospinel was developed. • LiCu-F has a mean particle size of 59.8 nm and a crystallite size of 45.9 nm. • LiCu-F exhibited sufficient antimicrobial activity and can be used in biological applications. • Within 60 min, LiCu-F exhibited bacteriostatic and bactericidal effects on S. aureus and E. coli. • LiCu-F had lower binding energy (−29.16 kcal/mol) for E. coli than for S. aureus (−38.89 kcal/mol). An aqueous carob leaf extract was employed in the current study as a biogenic agent (reducing and capping agents) for the synthesis of novel bimetallic lithium and copper-based nanospinel ferrites (LiCu-F) with antibacterial activity. LiCu-F has a considerable number of surface -OH groups, a BET-specific surface area of 72.5 m2/g, a mean particle size of 59.8 nm, and a crystallinity index of 78.9%, according to the results of the physicochemical characterisation of the ferrite. Within the first 60 min, LiCu-F showed bacteriostatic and bactericidal effects on S. aureus and E. coli based on the time-kill assay. 0.4 mg of LiCu-F demonstrated 67.9% bacteriostatic effects on E. coli while exhibiting 100% inactivation of S. aureus strains, demonstrating that the gram-positive bacteria are more susceptible to LiCu-F. The computational molecular docking analysis demonstrated that LiCu-F has a higher binding affinity for S. aureus (-38.89 kcal/mol) than E. coli (-29.16 kcal/mol), which is consistent with the experimental findings. With an LD 50 of 1000 mg per kg of body weight based on a computational prediction tool, LiCu-F is cytotoxic to bacteria and can cause DNA damage and cell death in bacterial strains. [Display omitted] [ABSTRACT FROM AUTHOR]

Here, trichlorovinylsilane-modified-chitosan (TVS-m-CS) film is synthesized and explicated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and X-ray diffraction (XRD). The SEM micrograph of TVS-m-CS revealed smooth structure with bulge surface. The TVS-m-CS antibacterial activity was evaluated using the broth dilution and agar diffusion methods. Results herein indicated that the TVS-m-CS exhibited enhanced water solubility (67 mg/mL) compared to the cross-linked chitosan (CS) film (5.5 mg/mL). Notably, TVS-m-CS showed a significantly enhanced antibacterial activity against E. coli, S. aureus, E. faecalis, Kleb spp. and methicillin-resistant Staphylococcus aureus (minimum inhibitory concentration [MIC] = 0.078–0.156 mg/mL and minimum bactericidal concentration [MBC] = 12.5–3.12 mg/mL) than the original CS film. Unlike most quaternized chitosan derivatives, the TVS-m-CS was prepared via an easy and simple route and exhibited a comparatively high antibacterial performance. The time-kill study revealed that 5 mg/mL TVS-m-CS exposed to the bacteria cells is sufficient to give a ~ 0.08 log10 reduction (> 99.9% kill rate) within 24 h. [ABSTRACT FROM AUTHOR]

The abundant availability of toxic H 2 S in many industrial and natural resources and its low thermodynamic decomposition makes it a viable economic source for the production of environmentally clean fuel (H 2). Here, a highly efficient In 2 S 3 /AgIO 3 photoanode and Pt/C–based waterproofed carbon fibre cathode were prepared for the recovery of H 2 and S from toxic H 2 S in a cyclic redox system of I−/I 3 −. The H 2 S was oxidized to S by I 3 − in the photoanode compartment and H+ was efficiently reduced to H 2 in the photocathode region. A maximum H 2 and S production rate of ∼0.26 mmol h−1 cm−2 and ∼0.23 mmol h−1 cm−2 were achieved, respectively and the photocurrent density of ∼0.9 mA cm−2 was attained during the entire operation. The In 2 S 3 /AgIO 3 photoanode exhibited high energy conversion efficiency and polysulfides were not detected after the reaction, suggesting that the toxic H 2 S was completely converted into H 2 and S. The proposed system with I−/I 3 − redox provides an energy-sustaining method for simultaneous treatment of toxic H 2 S and clean fuel production. Image 1 • Novel In 2 S 3 /AgIO 3 photosensitive anode was fabricated and characterized. • In 2 S 3 /AgIO 3 supported with I−/I 3 − redox couples rapidly decomposed H 2 S into H 2 and S. • High recovery rates up to ∼0.26 mmol h−1 cm−2 and ∼0.23 mmol h−1 cm−1 for H 2 and S obtained. • Open-circuit potential and photocurrent reached 0.68 V and ∼0.9 mA cm−2 during 10 h operation. • The In 2 S 3 /AgIO 3 photoanode exhibited high energy conversion efficiency. [ABSTRACT FROM AUTHOR]

A novel hydrophilic porous alginate-based polyHIPE (AGA) was synthesized via an oil-in-water emulsion templating approach. AGA was used as an adsorbent for removing methylene blue (MB) dye in single- and multi-dye systems. BET, SEM, FTIR, XRD, and TEM were used to characterize AGA to elucidate its morphology, composition and physicochemical properties. According to the results, 1.25 g/L AGA adsorbed 99 % of 10 mg/L MB in 3 h in a single-dye system. The removal efficiency decreased to 97.2 % in the presence of 10 mg/L Cu2+ ions and 40.2 % when the solution salinity increased to 70 %. In a single-dye system, the experimental data do not match well with the Freundlich isotherm, pseudo-first order, and the Elovich kinetic model, however, in a multi-dye system, it fit well with both extended Langmuir and the Sheindorf-Rebhun-Sheintuch. Notably, AGA removed 66.87 mg/g in a dye solution containing only MB, whereas 50.14–60.01 mg/g adsorption of MB was accomplished in a multiple-dye system. According to the molecular docking analysis, the dye removal process involved chemical bonds between the functional groups of AGA and the dye molecules, hydrogen bonds, hydrophobic and electrostatic interactions. The overall binding score of MB decreased from −26.9 kcal/mol in a single-dye system to −18.3 kcal/mol in a ternary system. • Alginate-based polyHIPE was synthesized via the emulsion templating technique. • >95 % of cationic dye was adsorbed by the polyHIPE in single and multi-dye systems. • PolyHIPE exhibited high selectivity towards MB in the presence of dye interferents. • Dye removal process involved mainly hydrogen bonds and physicochemical in nature. • After the fifth adsorption-desorption cycle, the polyHIPE performance is high. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Co–Fe LDH was used as precursor for the preparation of CoO–NiFe 2 O 4 mixed metal oxides catalyst. • CoO–NiFe 2 O 4 accomplished <94% decolorization of azo dye (EB) within 120 min. • Synergistic effects of CoO–NiFe 2 O 4 –photocatalyzed oxidation and Fenton-like reaction is established. • Decolorization efficiency significantly reduced to 19.8% in the alkaline conditions. • OH, O 2 – and photogenerated hole (h+) were responsible for the EB decolorization. Abstract Magnetic CoO–NiFe 2 O 4 catalyst was successfully fabricated from layered double hydroxide through a simple co-precipitation and calcination method, and for the first time applied as a novel Fenton-like catalyst for the decolorization of Eriochrome black T dye (EB). The characteristics results demonstrated that CoO–NiFe 2 O 4 exhibits a broad pore size distribution in the range of 5–40 nm, large specific surface area (363.6 m2 g–1) with the high structural stability and saturation magnetization (83.2 emu g–1), hence, can be easily recycled for five subsequent runs without significant activity loss. The catalytic activity of CoO–NiFe 2 O 4 was systematically evaluated under varying reaction conditions including initial pH, catalyst dosage, initial dye and H 2 O 2 concentrations. Under the optimal conditions, the CoO–NiFe 2 O 4 accomplished ∼87–97% decolorization of EB within 120 min. Here, the possible catalytic mechanism for EB decolorization is proposed and concluded to be multi-process induced by OH, O 2 − or h+ in the Fenton-like system. [ABSTRACT FROM AUTHOR]

Health concerns have been raised over the excessive occurrences of antibiotics such as tetracycline in aquatic environments. Adsorption is a simple and cheap technique for the removal of pharmaceuticals from industrial wastewater. To date, limited information exists on the fate, economical treatment and safe disposal of spent adsorbents in the environment, and this is often considered as the main drawback of adsorption. In this article, an alternative strategy to dispose and reuse spent inorganic adsorbents is proposed. We synthesized CoO/CuFe2O4 mixed metal oxide from layered double hydroxides by a modified co-precipitation and calcination method at 500 °C for 5 h. CoO/CuFe2O4 has a 348.5 m2/g surface area, pH point zero charge of 5.8 and an average pore diameter of 5.8 nm. Results show that the tetracycline removal efficiency at pH 6 reached 96.6% and 84-87.3% in the absence and in the presence of 4 g/L competing ions (Cl− and NO3−), respectively. Moreover, CoO/CuFe2O4 retained stable activities, of about 90%, over five consecutive recycling runs. Spent CoO/CuFe2O4 was reused as a catalyst in the presence of sunlight for degradation of azo dye, and this is the first report of achieving ~ 77% discolouration of eriochrome black T dye using a recycled adsorbent. [ABSTRACT FROM AUTHOR]

Here, pH-responsive engineered polymeric composites were fabricated from sodium alginate and mixed Cu/Zn oxides. The resulting alginate–Cu x Zn 1−x O composites were characterized by FTIR, SEM and XRD, then used as an efficient carrier for the antiretroviral drug (zidovudine, AZT) and exhibited remarkable antibacterial properties. The resulting polymeric composites had specific surface areas of 185.2–198.6 m 2 /g as confirmed by the Brunauer–Emmett–Teller analysis. The metal oxide distribution within the alginate matrix was confirmed from the X-ray diffraction and scanning electron microscopy analyses. The zidovudine, an antiretroviral drug was encapsulated in 30 mg of alginate–Cu 0.7 Zn 0.3 O with 68% encapsulation efficiency. The release of AZT in simulated intestinal fluid (pH 7.4) was studied, a slow and sustained release of AZT (~96.2%) was observed. The AZT release kinetics is sufficiently described by the Korsmeyer–Peppas model and follows the Fickian transport profile. Results herein demonstrated that A–Cu 0.7 Zn 0.3 O, A–Cu 0.3 Zn 0.7 O and Cu 0.5 Zn 0.5 O exhibited excellent bacterial devastation property. A dose of 8 μg/mL A–Cu 0.7 Zn 0.3 O and 13 μg/mL A–Cu 0.3 Zn 0.7 O are sufficient to completely killed E. coli DH5a and S. aureus NSUHS-151 within 24 h. [ABSTRACT FROM AUTHOR]

Magnetic biocomposite (MB) was fabricated by co-precipitation of palm seed-based biochar in the presence of Fe3O4particles. The MB sorption behaviour was investigated using nickel as the target pollutant. The MB characterisation revealed that its maintained micro-mesoporous character and high saturation magnetisation (65.8 Am2/kg) enable it to be separated from a solution using a magnet. The nickel removal efficiency of MB, 87% (28 mg/g), was achieved at pH 3; however, this was reduced to 45–75% (15–24 mg/g) in the presence of competing ions. The isotherms and kinetics studies revealed a monolayer interaction via a two-stepped sorption mechanism. [ABSTRACT FROM AUTHOR]

Highly robust composite photocatalyst (WO3/MIL-53(Fe)) was synthesized and characterised. WO3/MIL- 53(Fe) exhibits remarkable photocatalytic efficiency for reduction of Cr(Vi) and oxidation of 2,4-dichlorophenoxyacetic acid (2,4-D) organochlorinated herbicide. After 240 min sunlight irradiation, only ~30% reduction ratio of Cr(VI) was recorded in the presence of WO3. However, about 70% and 94% Cr(Vl) reduction were achieved in the presence of MlL-53(Fe) and WO3/MIL-53(Fe), respectively. The removal efficiency proceeds more rapidly in the binary mixture of 2,4-D and Cr(VI) than in the single component system, indicating synergetic effect between the photooxidation and reduction reactions. 02•- played a key role in the reduction of Cr (VI) and h+ is confirmed to be the dominant active species in the degradation of 2,4-D. [ABSTRACT FROM AUTHOR]

• High-performance WO 3 /MIL-53(Fe) bifunctional composite photocatalyst was fabricated and characterised. • Efficient degradation of toxic organochlorinated herbicide from low concentration acidic solutions achieved. • Enhanced catalytic efficiency and elimination rate of WO 3 /MIL-53(Fe) were recorded for 2,4-D–Cr(VI) multicomponent system. • The positive charged surface of WO3/MIL-53(Fe) at pH

Magnetic chicken bone biochar (MCB) was fabricated and characterised. The specific surface area, magnetisation value and pH pzc of the MCB were found to be 328 m 2  g −1 , 64.7 emu/g and 8.3 respectively. The adsorptive performance of MCB for rhodamine B dye (RB) and tetracycline (TC) removal in a single and two-stage stirred adsorber (TSA) was evaluated. The TSA reduced the pressure drops, mass transfer resistances, and fouling of the adsorbent. 63.0 g MCB is required to remove 75% of RB and TC in a single-stage system within 12 h. However, the optimised TSA confirmed that 33.2 g of MCB is needed to achieve 96% removal of TC and 22.2 g for RB within 180 min of 100 mgL −1 effluent solutions. The sorption was suitably described by the Freundlich mechanism. Based on the comparative performance, the MCB is considered a viable efficient and magnetically separable alternative adsorbent. [ABSTRACT FROM AUTHOR]

Magnetic chicken bone-based biochar (MCBB) was successfully prepared and efficiently adsorbed rhodamine-B (RB) dye and tetracycline (TC) in multi-component systems. The magnetisation value, surface area, and pHpzc of the MCBB were found to be 66.5 emu/g, 328 m2/g, and 8.3, respectively. RB has higher saturation capacity (96.5 mg/g) and occupies more active sites on MCBB, thus limiting the sorption of TC with lower saturation capacity (63.3 mg/g). Langmuir isotherm suitably describes the sorption process in a single-component system; however, the multi-component system was well fitted to the Sheindorf-Rebhun-Sheintuch model. The selectivity factor values confirmed that MCBB had higher adsorption affinity toward RB than TC. The intraparticle diffusion model played a significant role in the sorption process. The MCBB can be easily desorbed with base-spiked H2O and reused without loss in stability or structural integrity. [ABSTRACT FROM AUTHOR]

High-performance activated carbon-zinc oxide (Ac–ZnO) nanocatalyst was fabricated via the microwave-assisted technique. Ac–ZnO was characterized and the results indicated that Ac–ZnO is stable, had a band gap of 3.26 eV and a surface area of 603.5 m2g−1, and exhibited excellent adsorptive and degrading potentials. About 93% phenol was adsorbed within 550 min of reaction by Ac–ZnO. Impressively, a complete degradation was achieved in 90 min via a photo-Fenton/Ac–ZnO system under optimum conditions. An artificial neural network (ANN) model was developed and applied to study the relative significance of input variables affecting the degradation of phenol in a photo-Fenton process. The ANN results indicate that increases in both H2O2 and Ac–ZnO dosage enhanced the rate of phenol degradation. The highest rate constant at the optimum conditions was 0.093 min−1 and it was found to be consistent with the ANN-predicted rate constant (0.095 min−1). [ABSTRACT FROM AUTHOR]

Chitosan-based magnetic nanobeads (CBN) were facilely synthesised and applied for selective recovery of boron from highly-saline wastewater. The CBN was characterised, and the results showed that the nanobeads are thermally and mechanically stable to withstand deterioration, had a saturation magnetisation of 65.25 emu/g, the surface area of 635 m 2 /g and nanobeads size of ∼2.6–3.8 nm. An artificial neural network (ANN) model and Box-Behnken design (BBD) were developed and applied to study the relative effect and significance of input variables affecting boron sorption. Under optimised conditions, 89, 78 and 70% boron removal efficiencies were recorded at pH 7.0 in distilled water, highly-saline water and boron-spiked seawater respectively. The combination of intraparticle diffusion model and pseudo-second-order rate equation was applicable to describe the sorption kinetics. [ABSTRACT FROM AUTHOR]

A new Mg-doped Zn 0.5 Ni 0.5 Fe 2 O 4 (Mg–FZN) photocatalyst was synthesised using a simple co-precipitation-doping technique to develop a dual-function material with the ability to degrade hazardous and refractory pollutants and inactivate bacterial strains. The characterization results revealed that Mg-FZN is an n -type semiconductor with a conduction band of −0.413 eV, an average pore width of 2.32 nm, and a crystal size of 31.45 nm. The photocatalytic activity of Mg-FZN was assessed based on the degradation of 2,4,5-trichlorophenol and achieved 83.8% degradation efficiency under optimised conditions. The radical quenching results revealed that h + significantly contributed to the photodegradation process while •OH, and •O 2 − played key roles. Additionally, within 60 min, 25 mg of Mg–FZN had bactericidal effects on the bacteria E. coli and S. aureus in both the presence and absence of UV light. Mg–FZN showed H-bonding, electrostatic, and metal-contact interactions with the amino acid residues of the bacterial protein with high binding scores (−4.711 kcal/mol and −5.872 kcal/mol), according to molecular docking. [Display omitted] • Mg-doped binary metal ferrite (Mg-FZN) was synthesised via facile co-precipitation method. • Mg-FZN is an n -type semiconductor with a specific surface area of 71.8 m2/g. • 10 mg of Mg-FZN degraded 83.8% of trichlorophenol at pH 3 with a rate of 0.046 min−1. • 15 mg of Mg-FZN exhibited bactericidal effects on bacteria strains within 60 min. • The binding mechanism of bacteria protein and Mg-FZN revealed by molecular docking. [ABSTRACT FROM AUTHOR]

Porous magnetic hybrids were synthesized and functionalized with glycidol to produce boron-selective adsorbent. The magnetic hybrid (MH) comparatively out-performed the existing expensive adsorbents. MH had a saturation magnetisation of 63.48 emu/g and average pore diameter ranging from meso to macropores. The magnetic hybrids showed excellent selectivity towards boron and resulted in 79–93% boron removal even in the presence of competing metal ions (Na + and Cr 2+ ). Experiments were performed in a column system, and breakthrough time was observed to increase with bed depths and decreased with flow rates. The batch experiments revealed that 60 min was enough to achieve equilibrium, and the level of boron sorption was 108.5 mg/g from a synthetic solution. Several adsorption-desorption cycles were performed using a simple acid–water treatment and evaluated using various kinetic models. The spent adsorbents could be separated easily from the mixture by an external magnetic field. The cost-benefit analysis was performed for the treatment of 72 m 3 /year boron effluent, including five years straight line depreciation charges of equipment. The net profit and standard percentage confirmed that the recovery process is economically feasible. [ABSTRACT FROM AUTHOR]

Hydroxyl-enhanced materials are considered promising for boron adsorption. But, the use of these materials is hindered by issues of selectivity and separation notably in the presence of co-existing ions. Therefore, magnetic chitosan-based microbeads (MC) were synthesized and functionalized with a glycidol to produce boron-selective adsorbent (MCG). The resulting multi-hydroxyl microbeads were found to be a better substitute to the existing boron adsorbents. The adsorbents were characterized by scanning electron microscopy (SEM), and thermal gravimetric analysis (TGA). The BET surface area and vibrating sample magnetometry analyzes confirmed that the functionalized beads had a saturation magnetization, surface area, pore size, and diameter of 46.53 Am 2 /kg, 598 m 2 /g, 2.9 nm and ∼ 150–400 μm respectively. Under optimized condition, the MCG showed high adsorption affinity and remarkable selectivity towards boron in the presence of co-existing metal ions (Cu 2 + , Fe 3 + , and Ni 2 + ) and salts of Mg 2 + , Ca 2 + , Na + and K + ions. MCG has 128.5 mg/g of boron loading capacity within the first 100 min, which is relatively higher than reported values. The spent beads were separated easily from the suspensions by an external magnet and reuse repeatedly. [ABSTRACT FROM AUTHOR]

The study describes the development of glucose-sensitive hydrogel and optimization of bovine serum albumin release profile from the hydrogel. To enhance the glucose sensitivity and improve the swelling behaviors of the hydrogel system, boric acid crosslinking, and freeze-thawing cycle techniques were used to prepare chitosan–poly(vinyl alcohol) hydrogel. The structure of the resultant hydrogel was confirmed by scanning electron microscopy and Fourier transform infrared spectroscopy. The experimental results revealed that the swelling of the hydrogel was influenced by the pH of the medium, and the hydrogel displayed explicit glucose-sensitivity under physiological conditions. The values of the diffusion exponent range between 0.34 and 0.44 and the diffusion of water into the gel system are assumed to be pseudo-Fickian in nature. Under optimized conditions, the cumulative Bovine serum albumin (BSA) drug releases ranged between 69.33 ± 1.95% and 86.45 ± 1.16% at 37 °C in the presence of glucose and pH 7.4, respectively. [ABSTRACT FROM AUTHOR]

Removals of tetracycline and photocatalytic degradation of phenol by Fe 3 O 4 /coffee residue (MCC) were investigated. Brunauer–Emmett–Teller (BET), vibrating sample magnetometer (VSM) and Boehm titration were employed to characterize MCC. Artificial neural network (ANN) model was developed to predict the tetracycline (TC) concentration in the column effluent. Maximum tetracycline adsorption capacity of 285.6 mg/g was observed in a batch system. High removal efficiency (87%) was obtained at 3.3 mL/min flow rate, 8.0 cm bed height and 50 mg/L influent TC concentration in a column system. Complete degradation of phenol by solar-Fenton was attained at 60 min irradiation time. Total organic carbon (TOC) removal increased to 63.3% in the presence of 1.0 g/L MCC, 1.2 g/L H 2 O 2 and solar irradiation. MCC showed remarkable potential to remove antibiotics from wastewater even in the presence of heavy metal (Ni 2+ ) via magnetic separation. [ABSTRACT FROM AUTHOR]

In discharged water, antibiotics and heavy metals frequently coexist, forming stable and recalcitrant complexes. Environmental concerns about how to efficiently treat this type of pollution are growing. Using Fe and Al electrodes, electrocoagulation (EC) was applied to remove tetracycline (TC) as a single pollutant as well as TC-nickel ions in a binary mixture from water. The effects of critical variables and the TC-Ni molar ratio (1:1, 1:2, and 2:1) were studied. The Fe electrode achieved 99.3% TC removal after 60 min in a single pollutant system containing 15 mgL−1 of TC, while the Al electrode achieved 99.8% removal in 20 min at optimal conditions. The EC process demonstrated excellent electrodegradation efficiency towards TC-Ni complexes. When the TC to Ni2+ ratio was 1:1 and 1:2, respectively, TC elimination was 100% in 10 min and 99.6% in 20 min. We noted that a sufficient amount of Ni2+ could increase TC decomposition by electrocatalysis. The amount of hydrogen gas produced after treatment of a 0.2 L TC solution alone is 22.2–13.99 mol m−3, whereas it was 27.2–40.8 mol m−3 in the TC-Ni binary mixture, which can generate more than 35% of the electrical energy needed to power the EC system. To evaluate the generated sludge, FTIR analysis was performed. • Antibiotic-heavy metal complexes were removed by electrocoagulation. • Al anode outperformed electrocoagulation with Fe anode in a single pollutant system. • Within 20 min, the Al anode removed ∼100% TC, while Fe anode removed ∼98% in 40 min. • The EC process eliminated 100% of the TC-Ni binary mixture in 20 min at pH 7. • For a binary mixture, the EC had a rapid removal rate than for a single pollutant. [ABSTRACT FROM AUTHOR]

Alginate encapsulated nano-hydroxyapatite beads were synthesized and characterized by Fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface analysis, and X-ray diffraction. Their adsorptive potential for Ni2+and rhodamine B was explored in batch mode and by fixed-bed column passage. In the batch system, maximum uptake capacity for Ni2+was 360 mg g−1and 480 mg g−1for rhodamine B. In the presence of humic acid, sorption was enhanced. For the continuous-flow system, adsorption was effective at low flow rate. For both pollutants, mass transport resistance increased during adsorption. The overall rates of rhodamine B and Ni2+uptake were found to be controlled by external mass transfer. [ABSTRACT FROM AUTHOR]

Adsorption of a binary mixture of anionic dyes onto chitosan-based hydrogel (SAH) was investigated. Erichrome black T (EBT) and reactive blue 2 (RB2) were used as a model azo and anthraquinone dyes respectively. Adsorption potential of SAH was investigated under laboratory conditions as a function of initial concentration (50–400 mg/L), temperate (25–55 °C) and solution pH. In a single dye system, adsorption trend follows the Langmuir and pseudo second-order kinetics models. The overall rates of EBT and RB2 were noted to be controlled by film, pore and particle diffusions throughout the adsorption period. For binary dye-system, selectivity factor ( A ) was introduced into the extended Langmuir model, and the equilibrium data fitted well with the modified isotherm model ( R 2 = 0.96–0.99). The values of Δ G ° (−17.012 to −22.473 kJ/mol) of the binary dye system are within the ranges of physisorption mechanism. Box-Behnken model was utilized to estimate the competitive effects of the variables in binary dye system, and the experimental data indicates higher affinity for EBT (520.21 mg/g) compared with RB2 (407.05 mg/g). The reusability of SAH has proven that the adsorbent is durable and cost-effective. [ABSTRACT FROM AUTHOR]

The impact of adding varying loadings (25–75%) of Ni 0.3 Zn 0.7 Fe 2 O 4 (NZF) nanoparticles into a TiO 2 photoanode sensitized with both natural and commercial dye molecules is reported herein. The photoconversion efficiency (PCE) of the DSSCs was found to be greatly improved by NZFs. Our findings show that NZF enhanced the PCE of NZF/TiO 2 –0.5/dye/Pt based DSSC by 51.5% for natural chlorophyll dye (spinach extract) and 33% for commercial ruthenium-based dye (Z-907) at an optimum loading of 50% w/w, compared to TiO 2 /dye/Pt DSSC devices. According to UV–Vis absorption spectroscopy, BET, and electrochemical impedance spectroscopy studies, higher dye loading, improved electron transportation, and lower electron recombination rates with electrolyte and oxidized dyes contributed to the improved performance of the NZF/TiO 2 –x hybrids based DSSCs. Based on the results of time-dependent stability studies, the NZF/TiO 2 –0.5/chlorophyll-based cell maintained 94.7% of its original photoconversion efficiency after 14 days before dropping to 87.8% over 30 days. [Display omitted] • Ni 0.3 Zn 0.7 Fe 2 O 4 (NZF) nanoparticles were synthesized and loaded onto TiO 2 to produce NZF/TiO 2 – x hybrids. • NZF/TiO 2 – x hybrids exhibited higher surface area, lower energy bandgap and greater charge collecting efficiency than TiO 2. • NZF/TiO 2 – x hybrids and TiO 2 alone were used as photoanodes for synthetic and natural dye DSSCs. • NZF/TiO 2 – x hybrids achieved photovoltaic efficiencies of 8.46% (commercial dye) and 2.85% (natural dye). • NZF/TiO 2 –0.5 retained 87.8% of its performance over 30 days which is higher than other reported values. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ni 0.5 Zn 0.5 Fe 2 O 4 /carbon (NZF/C) composite was synthesized as counter electrode for DSSCs. • NZF/Cs were characterized using spectro-electrical, optical and cyclic voltammetry tools. • NZF/C-1 containing 50% carbon exhibited comparable efficiency with Pt electrode. • NZF/C-1 CE had a photon conversion efficiency of 7.18% and a FF of 55.57% for Z-907 dye. • NZF/C-1 had a slightly higher charge transfer resistance of 4.33 Ω than Pt-based CE (4.04 Ω) The most notable counter electrode (CE) in dye-sensitized solar cells is platinum (Pt), which is expensive and scarce. Here, Ni 0.5 Zn 0.5 Fe 2 O 4 /carbon (NZF/C) composites containing different ratios of carbon were synthesized and used as novel counter electrodes. NZF/Cs have specific surface areas of 109.3–128.6 m2 g−1, pore sizes of 99.4–119.6 Å, and bandgap energies of 2.36–2.99 eV, according to the characterization results. The catalytic activities of NZF/C CEs were verified by electrochemical impedance spectroscopy and cyclic voltammetry. NZF/Cs demonstrated outstanding catalytic activities in the reduction of I 3 − and had performance comparable to Pt CEs in the dye-sensitized AgNP/TiO 2 DSSCs. For the natural betalain dye, NZF/C-1 CE demonstrated a 2.75% efficiency with a short circuit current density of 4.13 mA cm−2 and a fill factor of 50.71%, which was very competitive with Pt CE's 2.83% efficiency. During 30 days of stability testing, NZF/C-1 CE maintained a photon conversion efficiency of 7.18% and a fill factor of 55.57% for Z-907 synthetic dye. The high electrocatalytic activity of NZF coupled with the good conductivity of carbon black account for NZF/C performance. The results herein show that NZF/C can be used as a cost-effective and efficient substitute for Pt in DSSCs. [ABSTRACT FROM AUTHOR]

Pomegranate seed powder (PS) was functionalized with polyvinyl alcohol (PVA) and utilized for boron removal from the aqueous system. Results of Brunauer--Emmett--Teller (BET) surface area analysis and Boehm titration indicated notable decrease in total surface area and increase in acidic surface functional groups of PS after PVA modification. Enhanced sorption is indicative of complex formation between diol groups of the pomegranate seed powder--polyvinyl alcohol (PS–PVA) and borate ions. Under column test, the saturated sorption capacity of boron was noted to be dependent on flow rate and bed height. The developed central composite design (CCD) was adequate to elucidate the sorption mechanism. Mathematical modeling of the column data was conducted, and a modified-dose-response model was the most suitable to describe the breakthrough curve and observed to be consistent with CCD analysis. This is further supported by extensive error analyses conducted between the model predicted and experimental data. [ABSTRACT FROM PUBLISHER]

A cost-competitive MnFe-LDO–biochar hybrid catalyst was successfully synthesized via a simple yet efficient technique for the decomposition of metronidazole (MZ). MnFe-LDO–biochar was characterized by various techniques and the results revealed that it has a bandgap of 2.85 eV, high photocurrent response of 3.8 μA cm−2 and can be separated rapidly from the bulk solution by an external magnet due to its saturation magnetization of 28.5 emu g−1. Initially, in the dark condition, 20% of MZ was removed after 30 min when 20 mg L−1 MZ solution was treated with 50 mg MnFe-LDO–biochar in the presence of 6 mM H 2 O 2. The MZ degradation increased remarkably to ∼98% upon exposure to a UV light for 60 min. Under various processes, UV/MnFe-LDO–biochar/H 2 O 2 presented high degradation rate constant of 0.226 min−1 and lowest energy consumption cost of 0.38$ at 7.56 kWh m−3 which is ∼13 times lower than the degradation of MZ by the photolytic process under similar conditions. The MZ photocatalytic decomposition trend revealed a multiprocess mechanism influenced majorly by •OH and partly by h + and •O 2 −. Note that in MnFe-LDO–biochar/UV system; 5% of MZ degradation was observed after 120 min and reached 13% after 300 min. MnFe-LDO–biochar maintained ∼88% reuse efficiency after three consecutive recycling tests. • Hybrid reusable catalyst MnFe-LDO–biochar was fabricated via co-precipitation-calcination technique. • MnFe-LDO–biochar has a bandgap of 2.85 eV and a high photocurrent response of 3.8 μA cm−2 with interconnected pores. • UV/MnFe-LDO–biochar/H 2 O 2 photodegraded ∼98% of metronidazole (20 mg L−1) in 60 min. • Degradation of antibiotic was influenced majorly by.•OH/•SO 4 − and partly by h + /•O 2 −. • Electrical energy cost is 0.38$ for achieving ∼98% treatment efficiency at 7.56 kWh m−3. [ABSTRACT FROM AUTHOR]

Here, nitrogen and sulfur co-doped chicken bone-derived biocarbon (CB 0.5 –N,S) was prepared using thiourea and K 3 Fe(CN) 6 as a dopant and graphitization enhancer, respectively. The CB 0.5 –N,S possesses a suitable graphitization degree (0.87), improved wettable carbon surface, large specific surface area (1615.6 m2 g−1) and wide pore size (2.17 nm) suitable to accommodate fully solvated organic and aqueous electrolyte ions. Typically, CB 0.5 –N,S delivered a high specific capacitance of 493.9 F g−1 with excellent capacitance retention of 97.6% and low electrode resistance (R e) of ~0.82 and 0.98 Ω cm2 before and after 6000 cycling tests, respectively. Also, CB 0.5 –N,S//CB 0.5 –N,S symmetric supercapacitor was assembled in an aqueous (1 M H 2 SO 4 , 6 M KOH, 1 M Li 2 SO4) and organic electrolytes (1 M TEABF 4 /acetonitrile); and delivered a high energy-power output. 80.8 W h kg−1 and 59.7 W h kg−1 energy densities were delivered at a power density of 2.5 and 1.3 kW kg−1 in 2 M TEABF 4 /AN and 1 M H 2 SO 4 at 1 A g−1, respectively. After 30,000 epoch trains, the developed artificial neural network (ANN) model predicted the performance of the symmetric capacitor with values closely matched to the experimental results at an average desirability function of 0.96 and R2 of 0.964. Image 1 • Nitrogen and sulfur co-doped chicken bone-derived biocarbon (CB 0.5 –N,S) was prepared. • CB 0.5 –N,S delivered a high specific capacitance of 493.9 F g−1 with excellent capacitance retention. • CB 0.5 –N,S based symmetric supercapacitor was assembled in aqueous and organic electrolytes. • Machine learning-based model was developed to predict the electrochemical performance of CB 0.5 –N,S. • The electrode material exhibited low electrode resistance (R e) of 0.98 Ω cm2 after 6000 cycling tests. [ABSTRACT FROM AUTHOR]

• Cost-competitive hybrid (MnFe-LDO–biochar) photocatalyst was successfully prepared. • MnFe-LDO–biochar has a bandgap of 2.85 eV and a high photocurrent response of 3.8 μA. • Large surface area containing mixed metal oxide oxidizing sites of MnFe-LDO–biochar improved its antibiotic degradation. • 50 mg MnFe-LDO–biochar/K 2 S 2 O 8 degraded ∼98 % tetracycline within 60 min upon exposure to a UV light. • MnFe-LDO–biochar performed sufficiently in a wide practical pH without significant leaching. A high-efficiency layered double oxide-biochar hybrid (MnFe-LDO–biochar) catalyst was successfully synthesized by the co-precipitation-calcination process and used to effectively remove tetracycline (TC) pollution. The characterization results verified that MnFe-LDO–biochar possesses a specific surface area of 524.8 m2 g−1, appropriate bandgap (2.85 eV), a high photocurrent response (3.8 μA cm–2), a saturation magnetization of 28.5 emu g−1 and a mixture of interconnected pores. 40 % of TC was removed after 30 min when 50 mL TC solution (20 mg L−1) was treated with 50 mg MnFe-LDO–biochar in the dark and reached ∼98 % degradation rate within 240 min upon exposure to a UV light. Notably, in the presence of H 2 O 2 or K 2 S 2 O 8 , the degradation rate of MnFe-LDO–biochar was shortened to 60 min with an average pseudo-first-order rate constant of 0.0445 min−1. The antibiotic removal rate of the cost-competitive MnFe-LDO–biochar surpassed several reported materials and maintained ∼80 % reuse efficiency after 3rd successive cycles. The TC photodegradation mechanism is multiprocess induced majorly by OH and SO 4 − while h+ and O 2 − contributed partly to the mineralization. This work highlights the powerful synergistic combination of layered double oxide (LDO) and biochar. [ABSTRACT FROM AUTHOR]

The potential of solid olive wastes-based adsorbent (CuO−OC) with photocatalytic power was established for the removal of total phenolics and photocatalytic discolourization of high strength olive mill wastewater (OMW). Clear insight of the FTIR and Brunauer−Emmett−Teller analyses showed that oxygen-containing functional groups of CuO−OC likely participated in the adsorption of total phenols from the OMW via a π−π interaction, hydrogen bonding and electrostatic interaction. Also, the total pore volume of CuO−OC decreased from 0.068 to 0.052 cm3 g−1 after adsorption, which suggested that phenolics were trapped within the micro- and mesopores of CuO−OC. The adsorption kinetics revealed that ∼82.7–95% of the phenolic compounds were removed within the first 360 min which is relatively faster than adsorbents and methods reported elsewhere. The isotherm results showed that Redlich–Peterson equation fit the experimental data very well with least error (χ2 = 1.46–3.19) and high correlation coefficients (0.992–0.996), which suggested a mixture of hetero- and monolayer coverage of the phenolics on the CuO−OC surface. Results obtained herein are of practical interest and the reuse efficiency of CuO−OC remained ∼60% after 5 successive recycling. Image 1 • Potential of CuO-solid olive wastes for decontamination of olive mill wastewater established. • Adsorption equilibrium reached at 360 min with a removal efficiency of ∼82.7–95%. • CuO−OC performance is remarkable in a wide range of solution pH. • Reuse efficiency of CuO−OC remained ∼60% after 5 successive recycling. • Total phenols removal occurred via a π−π interaction, hydrogen bonding and electrostatic interaction. [ABSTRACT FROM AUTHOR]

Abstract In this study, porous magnetic resin grafted chitosan (R- g -Ch) beads were prepared for removal of 4–chlorophenol and phenol from aqueous solutions. The R- g -Ch beads were characterized by vibrating sample magnetometer, Fourier-transform infrared spectroscopy, scanning electron microscopy and thermogravimetry methods. The removal of the phenolic compounds was optimized by varying the experimental conditions. Results herein are well fitted to the pseudo-second order kinetic and Langmuir isotherm. The maximum adsorption capacity of phenol and 4–chlorophenol were found to be 188.6 and 99 mg/g, respectively. The thermodynamic studies suggested that the adsorption process was exothermic, irreversible and feasible within the range of 298–318 K. [ABSTRACT FROM AUTHOR]

This article reports the efficient removal of Direct Red 80 (DR80) dye from aqueous phase using a semi-interpenetrating network (IPN) superabsorbent chitosan-starch (ChS) hydrogel. In the present investigation, the influence of initial pH, ChS dose, initial dye concentration, temperature and effect of salts on the sorption of DR80 dye was evaluated. A maximum swelling capacity of 15 g/g was determined for ChS hydrogel. The sorption equilibrium data demonstrated good agreement with Freundlich isotherm. The sorption process best fitted the pseudo-second order kinetic model. Maximum uptake capacity of the hydrogel was determined as 312.77 mg/g. The mean sorption energy ( E = 11.34–14.9 kJ/mol) demonstrated that DR80 sorption was mainly chemisorption. The temperature dependence data revealed the sorption process was spontaneous, endothermic and favourable at higher temperature based on the enthalpy (Δ H ° = +83.68 kJ/mol) value obtained. Boyd model confirmed intraparticle diffusion was the limiting step for DR80 uptake. In addition, sorption/desorption studies were performed to investigate the reusability of ChS hydrogel which demonstrated significant sorption for four consecutive cycles. [ABSTRACT FROM AUTHOR]

Here, human genomic DNA (hDNA) was encapsulated into supermacroporous alginate beads (SMPA) fabricated via microinjection and freeze-thawing cryogelation protocol. The scanning electron microscopy of the SMPA beads demonstrated smooth and centred burgled morphologies, while the encapsulated hDNA showed brilliant green fluorescence when visualised by fluorescence microscopy. The encapsulation efficiency of 89.1 − 96.7% was achieved when the concentration of hDNA and alginate varied within 0.05 − 0.075% and 0.5 − 0.75 wt%, respectively in the presence of 0.1 M CaCl2 crosslinking agent. ~80% hDNA was released over an extended period of 80 h when SMPA was immersed in a 0.5 M Na2HPO solution diluted with 10 mM Tris buffer (pH 7). Results and trends here demonstrated that SMPA beads have great potential to be used as a biocompatible vehicle for transporting biomacromolecules. [ABSTRACT FROM AUTHOR]

Non-edible oils ( Brassiceae family) were utilized for biodiesel production. Biodiesel was produced from four plants seeds oils and blended with ULSD. Two different methods were used for extraction of oil and the crude oil yields were 77.4 ± 2.14, 78.73 ± 3.1, 71.02 ± 2.15, 62.3 ± 3.4 (%) for B. napus, B. nigra, B. campestris and C. sativa plants, respectively. The oil obtained was pre-treated (chemical refinement through degumming, neutralization and bleaching) and was subjected to alkali-catalysed trans -esterification. Quality of produced biodiesel was compared with the fuel standards (ASTM D6751, ASTM D975, ASTM D7467 and EN 14214 and EN 590) and biodiesel properties were recorded to be in line with standards criteria except the kinematic viscosity of B. napus, B. nigra and C. sativa methyl esters and oxidative stability of B. napus and C. sativa . The fatty acids analysis by Gas Chromatography Mass Spectrometry revealed the highest proportion of erucic acid (43%) in methyl esters along with other minor components. The properties of methyl esters, both pure and blended were comparable with biodiesel fuels standards. So far, methyl esters properties of Brassiceae family plants are acceptable based on biodiesel standards and methyl esters can be used in blends with ULSD as a fuel. [ABSTRACT FROM AUTHOR]