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The increase in population have had a negative impact on the water quality environment despite the strong polices implemented on the wastewater treatment as the problem remains demanding. However, it is imperative to secure the environment of aquatic and human life. In this study, Anthill clay was activated with H2SO4 to obtain activated Anthill clay (AAC). The adsorbent was analyzed using the state of art techniques. The Brunner emitter teller (BET) surface area of AAC was 228.453 m2/g. The response surface methodology (RSM) was introduced for the optimization of lead (II) ion uptake where the removal efficiency of 92.73% was observed at optimum condition of 35 °C, 0.1g and 10 min respectively. Various adsorption parameter such as pH, temperature, adsorbent dosage and contact time was carried out. The interaction effect between the parameters were investigated. The Jovanovich model and Pseudo second order revealed the adsorption data fitted well for both isotherm and kinetics model. The thermodynamic results showed that the reaction is endothermic, spontaneous, and chemisorption in nature. From the various analysis conducted it can therefore be inferred that anthill clay can be effective and efficient for treatment of harmful substance present in wastewater.

This study explored the effective adsorptive performance of magnesium oxide (MgO) nanoparticles incorporated rice husk ash (RHA) to address the removal of Chromium (VI) and Lead (II) from mining wastewater from aqueous environment. MgO nanoparticles were synthesized using a magnesium salt precursor and moringa oleifera leaf extract and then impregnated onto RHA to create MgO-RHA nano composite. Different analytical techniques were employed to characterize the RHA and MgO-RHA nanocomposites. The prepared adsorbents were used in batch adsorptive studies and the concentrations of the metal ions were measured before and after treatment using atomic absorption spectrophotometry. Morphological analysis confirmed that the adsorbents developed exhibited a dispersed and porous nature. BET analysis revealed that RHA, MgO, and MgO-RHA had surface areas of 93.04, 32.02, and 102.71 m2/g, respectively. MgO-RHA outperforms RHA in removing metal ions due to its increased surface area and functionality. MgO-RHA demonstrated higher removal percentages of up to 79.20 % and 96.02 % for Cr(VI) and Pb(II), respectively. The Pseudo-second order kinetics and Langmuir isotherm demonstrated the highest degree of conformity to the experimental data, considering the coefficient of determination (R2), smallest value of SSE and chi-square (ᵪ2). Thermodynamic results indicated that the adsorption process was characterized by endothermicity, spontaneity and chemisorption controlled. In summary, the performance of the MgO-RHA nanocomposite surpassed that of RHA alone, which serves as a better adsorbent for metal ion removal.

In this work, zinc oxide (ZnO)/granular activated carbon (GAC) composites at different ZnO concentrations (0.25M-ZnO@GAC, 0.5M-ZnO@GAC, and 0.75M-ZnO@GAC) were prepared by an in-situ hydrothermal method and demonstrated synergistic photocatalytic degradation and adsorption of rhodamine B (RhB). The thermal stability, morphological structure, elemental composition, crystallographic structure, and textural properties of developed catalysts were characterized by thermal gravimetric analysis (TGA/DTG), scanning electron microscopy equipped with energy dispersive-x-ray (SEM-EDS), X-ray diffraction (XRD), and Brunauer–Emmett–Teller (BET) analysis. The successful loading of ZnO onto GAC was confirmed by SEM-EDS and XRD analysis. The BET surface areas of GAC, 0.25M-ZnO@GAC, 0.5M-ZnO@GAC, and 0.75M-ZnO@GAC were 474 m2/g, 450 m2/g, 453 m2/g, and 421 m2/g, respectively. The decrease in GAC could be attributed to the successful loading of ZnO on the GAC surface. Notably, 0.5M-ZnO@GAC exhibited the best photocatalytic degradation efficiency of 82% and 97% under UV-A and UV-C light over 120 min, attributed to improved crystallinity and visible light absorption. The photocatalytic degradation parameters revealed that lowering the RhB concentration and raising the catalyst dosage and pH beyond the point of zero charge (PZC) would favor the RhB degradation. Photocatalytic reusability was demonstrated over five cycles. Scavenger tests revealed that the hydroxyl radicals (•OH), superoxide radicals (O2−•), and photoinduced hole (h+) radicals play a major role during the RhB degradation process. Based on the TOC results, the RhB mineralization efficiency of 79.1% was achieved by 0.5M-ZnO@GAC. Additionally, GAC exhibited a strong adsorptive performance towards RhB, with adsorption capacity and the RhB removal of 487.1 mg/g and 99.5% achieved within 90 min of equilibrium time. The adsorption characteristics were best described by pseudo-second-order kinetics, suggesting chemical adsorption. This research offers a new strategy for the development of effective photocatalyst materials with potential for wider wastewater treatment applications.

This paper reports the synthesis of magnetic lipase/Cu3(PO4)2 hybrid nanoflowers via a rapid ultrasonication method. The enzyme immobilization and nanoflower growth mechanism can be described as the (a) Fe2+, Cu2+, and phosphate “binding”, (b) metal phosphate crystals formation, (c) formation and growth of metal phosphate crystals to form plate-like structures, and (d) self-assembly of plate structures that forms a flower-like structure. Some factors contributing to the morphology of the hybrid nanoflowers structure includes the time and concentration of lipase were studied. The effect of temperature, pH, and duration on the enzyme immobilization yield were also studied. In addition, the strong magnetic property (9.73 emu g−1) of the nanoflowers resulted in higher retrievability and reusability after repeated usage. Furthermore, the catalytic activity of lipase/Cu3(PO4)2 hybrid nanoflowers was investigated and the ideal conditions were determined whereby, the maximum activity was calculated to be 1511 ± 44 U g−1, showing a catalytic enhancement of 89% in comparison to free lipase. The reusability study showed that, after 5 cycles, the magnetic lipase/Cu3(PO4)2 nanoflowers successfully retained 60% of its initial activity. From the results obtained, it is worth noting that, the magnetic lipase/Cu3(PO4)2 hybrid nanoflowers are highly efficient in industrial biocatalytic applications.

There is increasing demand of natural food preservative in food manufacturing industry as it is the key to meet consumers’ preferences towards healthier food choice. Plant is one of the primary sources of bioactive compounds to be used as the natural food preservatives. More than 10,000 types of bioactive compounds that possess antimicrobial properties have been found in the plants around the world. Still, the possibility of many other plant species to be used as food preservative remain unexplored. This review paper describes the general procedures used to investigate the potential of the unexplored plants as the natural food preservative. The current challenges and way forward in using plant extract as a food preservative in the food industry are also discussed.

In daily life, energy plays a critical role. Hydrogen energy is widely recognized as one of the cleanest energy carriers available today. However, hydrogen must be produced as it does not exist freely in nature. Various methods are available for hydrogen production, including electrolysis, thermochemical technology, and biological methods. This study explores the production of biological hydrogen through the degradation of organic substrates by anaerobic microorganisms. Bacillus paramycoides and Cereibacter azotoformans strains were selected as they have not yet been studied for biological hydrogen fermentation. This study investigates the ability of these microorganisms to produce biological hydrogen. Initially, the cells were identified using cell morphology study, gram staining procedure, and 16S ribosomal RNA (rRNA) gene polymerase chain reaction. The cells were revealed as Bacillus paramycoides (MCCC 1A04098) and Cereibacter azotoformans (JCM 9340). Moreover, the growth behaviour and biological hydrogen production of the dark and photo fermentative cells were studied. The inoculum concentrations experimented with were 1% and 10% inoculum size. This study found that Bacillus paramycoides and Cereibacter azotoformans are promising strains for hydrogen production, but further optimization processes should be performed to obtain the highest hydrogen yield.

The large capacity of wastewater production due to rapid growth of industries has resulted in limited water resources. The need to protect and conserved water resources have enforced researchers worldwide to focus on the development of an effective, economical and environmentally friendly novel materials. In this study, green synthesis of zinc oxide nanoparticles (ZnONPs) using T. diversifolia leaf extract by hydrothermal method was loaded on the surface of flamboyant pods (Delonix regia) activated carbon (FPAC). The developed ZnONPs loaded on the surface flamboyant pods activated carbon (ZnONPs-FPAC) was used successfully to remove of methylene blue (MB) from aqueous solution. The developed FPAC, ZnONPs and ZnONPs-FPAC were characterized UV–Vis spectroscopy, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX), Transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) techniques. The antibacterial activity of the synthesized FPAC, ZnONPs and ZnONPs-FPAC were screened and the results revealed that ZnONPs has an excellent antibacterial activity when compared. Batch adsorption studies were conducted to investigate the influence of process parameters such as initial concentration, contact time, pH, adsorbent dosage and temperature on MB uptake. The high BET surface area of 794.48 m2/g and mesoporous ZnONPS-FPAC developed gave good adsorption capacity of 186 mg/g. Equilibrium adsorption data of MB were modelled using Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) isotherm model. The adsorption of MB onto ZnONPs-FPAC was best described by Freundlich model indicating surface heterogeneity, and pseudo-second-order kinetics according to %Δqe (normalized standard deviation), SSE (sum of square error), and R2 (coefficient of determination) values. The results of the thermodynamic suggest that the adsorption process of MB onto ZnONPs-FPAC is endotherm, favourable, spontaneous, and physical. In nature. The reusability of ZnONPs-FPAC was examined upto five cycles with no significant loss in removal efficiency. The mean free energy (E), and Enthalpy (ΔH) values calculated, suggested that the adsorption mechanism of MB on ZnONPs-FPAC is dominated by physical adsorption.

Microalgae are an excellent source of bioactive compounds for the production of a wide range of vital consumer products in the biofuel, pharmaceutical, food, cosmetics, and agricultural industries, in addition to huge upstream benefits relating to carbon dioxide biosequestration and wastewater treatment. However, energy-efficient, cost-effective, and scalable microalgal technologies for commercial-scale applications are limited, and this has significantly impacted the full-scale implementation of microalgal biosystems for bioproduct development, phycoremediation, and biorefinery applications. Microalgae culture dewatering continues to be a major challenge to large-scale biomass generation, and this is primarily due to the low cell densities of microalgal cultures and the small hydrodynamic size of microalgal cells. With such biophysical characteristics, energy-intensive solid–liquid separation processes such as centrifugation and filtration are generally used for continuous generation of biomass in large-scale settings, making dewatering a major contributor to the microalgae bioprocess economics. This article analyzes the potential of electroflotation as a cost-effective dewatering process that can be integrated into microalgae bioprocesses for continuous biomass production. Electroflotation hinges on the generation of fine bubbles at the surface of an electrode system to entrain microalgal particulates to the surface. A modification of electroflotation, which combines electrocoagulation to catalyze the coalescence of microalgae cells before gaseous entrainment, is also discussed. A technoeconomic appraisal of the prospects of electroflotation compared with other dewatering technologies is presented.