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The ultrafiltration mixed matrix membrane (UF MMMs) process represents an applicable approach for the removal of diluted acetic acid at low concentrations, owing to the low pressures applied. The addition of efficient additives represents an approach to further improve membrane porosity and, subsequently, enhance acetic acid removal. This work demonstrates the incorporation of titanium dioxide (TiO2) and polyethylene glycol (PEG) as additives into polysulfone (PSf) polymer via the non-solvent-induced phase-inversion (NIPS) method to improve the performance of PSf MMMs performance. Eight PSf MMMs samples designated as M0 to M7, each with independent formulations, were prepared and investigated for their respective density, porosity, and degree of AA retention. Morphology analysis through scanning electron microscopy elucidated sample M7 (PSf/TiO2/PEG 6000) to have the highest density and porosity among all samples with concomitant highest AA retention at approximately 92.2%. The application of the concentration polarization method further supported this finding by the higher concentration of AA solute present on the surface of the membrane compared to that of AA feed for sample M7. Overall, this study successfully demonstrates the significance of TiO2 and PEG as high MW additives in improving PSf MMM performance.

The utilization of lignocellulose biomass as an alternative source of renewable energy production via green technology is becoming important, and is in line with sustainable development goal initiatives. Lignocellulolytic bacteria, such as Bacillus spp., can break down biomass by producing hydrolytic enzymes, which are crucial in the successful conversion of biomass or lignocellulosic material into renewable energy. This information gave rise to this study, where municipal solid waste sediments of a sanitary municipal solid waste landfill were sampled and screened, and lignocellulolytic bacteria were isolated and characterized. Samples were taken from four different locations at the Pulau Burung landfill site in Malaysia. Lignin and starch were used as sources of carbon to identify potential bacteria that exhibit multi-enzymatic activity. The growth rate and doubling time of bacterial isolates in lignin and starch were taken as the criteria for selection. Eleven bacterial isolates were screened for cellulase activity using iodine and Congo red dyes. The cellulase activity of these isolates ranged from 0.8 to 1.7 U/mL. We carried out 16S rRNA gene sequencing to identify the phyla of the selected bacterial isolates. Phylogenetic analysis was also conducted based on the 16S rRNA sequences of the bacterial isolates and related Bacillus species, and a tree was generated using the Neighbor-Joining method. In this study, Bacillus proteolyticus, Bacillus Sanguinis, Bacillus spizizenii, Bacillus paramycoides, Bacillus paranthracis and Neobacillus fumarioli were identified as promising bacteria capable of expressing lignocellulolytic enzymes and degrading the lignocellulosic biomass present in municipal solid waste.

Massive generation of natural waste fiber from agricultural industries followed by improper disposal management might result in a detrimental effect on our ecosystem contributing to various types of environmental pollution. With the growing significance of climate change, an effort is being undertaken by utilizing natural waste fiber into eco-friendly insulation panels to reduce the environmental impact of buildings. In this research, a composite panel was developed from spent mushroom substrate (SMS) and empty fruit bunch (EFB) fibers via a sandwich technique. Five samples were made, each with a different fiber ratio (100 SMS: 0 EFB, 80 SMS: 20 EFB, 60 SMS: 40 EFB, 40 SMS: 60 EFB, and 0 SMS: 100 EFB) at density 0.8 g/cm3. Fourier transformation infrared (FTIR) Soxhlet extraction followed by thermogravimetric analysis (TGA) indicated that the SMS and EFB fibers were relevant for fabrication into a composite panel for thermal insulation. Thermal conductivity, thermal resistance, and thermal diffusivity values for these five composite samples were 0.231 to 0.31 W/(mK), 0.0194 to 0.0260 m2K/W, and 0.2665 to 0.3855 mm2/s, respectively. The flexural strength of the composite was at the range 15.61 to 23.62 MPa. These research findings suggest that the fabrication of a sandwich composite panel from SMS and EFB fiber is a promising alternative way to utilize natural waste fiber.

Patent Blue (PB) dye removal from an aqueous medium was investigated using pineapple fruit peel biochar (PFPB). The presence of functional groups and surface characteristics of PFPB was studied using Fourier transform infrared spectra (FTIR) and scanning electron microscopy (SEM). A study was conducted to assess the pH effect, contact time, concentration of dye, biochar dose, speed of agitation, and temperature on removal of PB (Patent Blue) dye from an aqueous medium by PFPB. The highest 95% elimination of PB dye was reported at pH 2 by PFPB with 600 mg/L concentration of PB dye. Equilibrium studies divulged the favorable adsorption that followed the Langmuir isotherm with a monolayer uptake potential of 10.29 mg/g. Findings of kinetics disclosed that adsorption results were properly explained by the pseudo second-order model. The adsorption phenomenon was exothermic and spontaneous, as observed by thermodynamic variables. PFPB reflected a 37% uptake capacity of PB dye for up to five consecutive cycles in the adsorption and desorption study. A phytotoxicity study exhibited that PFPB-treated PB dye solution enhanced the growth of seedlings and biochemical constituents of lentils. The findings of the present study indicate the immense potential of pineapple fruit peel biochar for anionic dye removal from wastewater systems. Thus, pineapple fruit peel biochar can be utilized as a promising green sorbent for the elimination of Patent Blue dye in industrial effluents, as it is widely available and converts wastewater into reusable assets.

The use of microalgae for the removal of contaminants such as total phosphorus (TP), total nitrogen (TN), chemical oxygen demand (COD), and other pollutants from palm oil mill effluent (POME) has recently received much attention. This study aimed to investigate the impact of POME as a nutrient on microalgal growth and the rate at which nutrients were removed. Three green microalgae species were isolated from Penang, Malaysia’s palm oil mill. The polyphasic approach, which combines morphological and molecular observations, was used for species identification. The three green microalgae were identified as Chlorella sorokiniana, Scenedesmus quadricauda, and Chlorococcum oleofaciens. All three green microalgae were cultivated in 25%, 50%, and 75% (v/v) of lab-scale palm oil mill effluent (LABT-POME) to investigate the growth of these three green microalgae in 100 mL of BBM. Under a light microscope and a scanning electron microscope (SEM), the morphological changes of those three green microalgae (before and after cultivation in 25%, 50%, and 75% dilution of (LABT-POME)) were observed. When cultivated in LABT-POME, C. oleofaciens showed the highest growth rate compared to the other two species of green microalgae. C. oleofaciens was able to remove more than 90% of total phosphorus (TP), total nitrogen (TN), and ammonia nitrogen from LABT-POME, as well as minimise soluble chemical oxygen demand (SCOD) by about 65%. The growth of C. oleofaciens was well fitted to the Verhulst growth kinetic model with an R2 value of 0.99 and a growth rate of 0.3195 day−1 (d−1). The results of this study show the ability of newly isolated green microalgae to remove nutrients (TP, TN, NH3–N, and SCOD) from POME, which could be used as an effective and environmentally friendly method to remove pollutants.

The need for energy resources is growing all the time, which means that more fossil fuels are needed to provide them. People prefer to consume chicken as a source of protein, and this creates an abundance of waste. Thus, microbial fuel cells represent a new technological approach with the potential to generate electricity through the action of electrogenic bacteria toward chicken manure, while reducing the abundance of chicken manure. This study investigated the effect of different pretreatment (thermal, alkaline, and sonication pretreatment) of chicken manure to improve the performance of a membrane-less microbial fuel cell (ML-MFC). Statistical response surface methodology (RSM) through a central composite design (CCD) under a quadratic model was conducted for optimization of the ML-MFC performance focusing on the COD removal efficiency (R2 = 0.8917), biomass (R2 = 0.9101), and power density response (R2 = 0.8794). The study demonstrated that the highest COD removal (80.68%), biomass (7.8539 mg/L), and power density (220 mW/m2) were obtained when the pretreatment conditions were 140 °C, 20 kHz, and pH 10. The polarization curve of the best condition of ML-MFC was plotted to classify the behavior of the ML-MFC. The kinetic growth of Bacillus subtillis (BS) showed that, in treated chicken manure, the specific growth rate µ = 0.20 h−1 and doubling time Td = 3.43 h, whereas, in untreated chicken manure, µ = 0.11 h−1 and Td = 6.08.

Prior to applying supported liquid membranes (SLM) with strip dispersion for separation of chromium (VI), copper and zinc, suitable chemical settings were determined through solvent extraction and stripping studies. More than 90% of copper and zinc could be simultaneously extracted with at least 3% (v/v) di-(2-ethylhexyl)phosphoric acid (D2EHPA) at a feed equilibrium pH in the range of 3.5–5.0. For stripping, theoretical model equations derived and experimental results revealed that suitable concentrations of lower acid strength reagents can strip metals that have weaker metal-extractant bond without significantly stripping metals that have a stronger metal-extractant bond. Therefore, in a setup comprising three compartments separated by two SLM, we propose to fill the three compartments in the following order: feed—strip dispersion containing low acid strength reagent—strong acid. An organic phase with 4% (v/v) D2EHPA was used. From stripping experiments, 0.2 mol/L pH 3 citrate buffer, which resulted in the highest copper recovery (88.8%) and solution purity (99.0%), was employed as the low acid strength reagent while the strong acid consisted of 1 mol/L sulfuric acid. In 26 h, 99.1% copper was recovered by citrate buffer with 99.8% purity and 95.1% zinc was recovered by sulfuric acid with 98.4% purity. Chromium (VI), copper and zinc could be separated effectively using this separation strategy.

The present study demonstrates the thermal stability and photocatalytic activity of TiO2-based nanotubes with respect to post-hydrothermal treatment. Titanate nanotubes were synthesized by adapting an alkali hydrothermal method from TiO2 sol using NaOH as a catalyst. The effect of post-hydrothermal heating on the properties—such as structure, morphology, textural properties, and activity—of as-synthesized one-dimensional titania nanostructure is investigated in detail. The characterizations are carried out using SEM, EDX, TEM, XRD, and a BET surface area analyzer. When heated in the presence of water in an autoclave, the protonated titanate phase of the nanotubes converts to anatase phase. Meanwhile, the tubular morphology is gradually lost as the post-hydrothermal heating duration increases. The photocatalytic activity was assessed utilizing the photo-oxidation of an amaranth dye. It is discerned that the as-prepared nanotubes are photocatalytically inactive but become active after post-hydrothermal processing. The activity trend follows the formation of the active phase—the titanate phase crystallizes into a photocatalytically-active anatase phase during post-hydrothermal heating. The effect of experimental parameters, such as reaction pH, dye concentration, and amount of catalyst, on the dye removal is studied. The findings also highlight that the role of holes/OH• is more prominent as compared to conduction band electron/O2−• for the removal of the dye. In addition, the photocatalyst exhibited excellent stability and reusability.

In this study, we aimed to observe how different operating parameters influenced the photocatalytic degradation of rhodamine B (RhB, cationic dye) and bromophenol Blue (BPB, anionic dye) over ZnO/CuO under visible light irradiation. This further corroborated the optimization study employing the response surface methodology (RSM) based on central composite design (CCD). The synthesis of the ZnO/CuO nanocomposite was carried out using the co-precipitation method. The synthesized samples were characterized via the XRD, FT-IR, FE-SEM, Raman, and BET techniques. The characterization revealed that the nanostructured ZnO/CuO formulation showed the highest surface area (83.13 m2·g−1). Its surface area was much higher than that of pure ZnO and CuO, thereby inheriting the highest photocatalytic activity. To substantiate this photocatalytic action, the investigative analysis was carried out at room temperature, associating first-order kinetics at a rate constant of 0.0464 min−1 for BPB and 0.07091 min−1 for RhB. We examined and assessed the binary interactions of the catalyst dosage, concentration of dye, and irradiation time. The suggested equation, with a high regression R2 value of 0.99701 for BPB and 0.9977 for RhB, accurately matched the experimental results. Through ANOVA we found that the most relevant individual parameter was the irradiation time, followed by catalyst dose and dye concentration. In a validation experiment, RSM based on CCD was found to be suitable for the optimization of the photocatalytic degradation of BPB and RhB over ZnO/CuO photocatalysts, with 98% degradation efficiency.

Water is an essential part of life, however, with continued modernization, it has become a dumping place for many pollutants including dyes. The polluted water can severely affect human health. Polluted water can enter into the human body through different channels, including the food web. Thus, it is very important for human beings and animals to have access to pollution free water. To get the knowledge of the pollutants, in this case, a dye, we need sensitive analytical procedure which could tell the amount of dye in water and also steps to get the pollutant removed from water. In this work, a liquid chromatography–mass spectrometry (LC-MS/MS) based analytical method was developed to determine malachite green. The method was developed after proper optimization of the experimental conditions, where finally, ethanol, a green solvent and formic acid, a food additive was selected to constitute the mobile phase in ratio 1.5:1.0. Different validation parameters were used to authenticate the reliability of the method. Based on the experiment results, the method was found to be linear in the range of 0.1 to 10 mg/L with an excellent correlation coefficient of 0.9995. The corresponding linear regression equation was found to be A = −6863.2 + 105,520 C, where A is the area of the peak and C is the concentration of malachite green. The precision study proves the reproducibility of LC-MS/MS procedure, throughout the precision experiment percent relative standard deviation (% RSD) was found to be between 0.709–1.893%. Similarly, the experiments on the recovery suggest a recovery of 97.28–98.75%. The new method was applied to check the amount of malachite green in environmental samples including the industrial wastewater. The wastewater sample was extracted using the solid phase extraction (SPE) technique, where a new adsorbent—wood apple hydrochar—was synthesized and used as the solid phase for the preparation of a solid phase extraction column to extract the malachite green. The synthesized adsorbent was characterized using different techniques. To conclude, the developed method can be used for determination of malachite green in environmental samples, and the SPE technique using wood apple hydrochar can successfully extract the dye from the water samples.

Microbial electrosynthesis is a new approach to converting C1 carbon (CO2) to more complex carbon-based products. In the present study, CO2, a potential greenhouse gas, was used as a sole carbon source and reduced to value-added chemicals (acetate, ethanol) with the help of bioelectrochemical reduction in microbial electrosynthesis systems (MES). The performance of MES was studied with varying electrode materials (carbon felt, stainless steel, and cobalt electrodeposited carbon felt). The MES performance was assessed in terms of acetic acid and ethanol production with the help of gas chromatography (GC). The electrochemical characterization of the system was analyzed with chronoamperometry and cyclic voltammetry. The study revealed that the MES operated with hybrid cobalt electrodeposited carbon felt electrode yielded the highest acetic acid (4.4 g/L) concentration followed by carbon felt/stainless steel (3.7 g/L), plain carbon felt (2.2 g/L), and stainless steel (1.87 g/L). The alcohol concentration was also observed to be highest for the hybrid electrode (carbon felt/stainless steel/cobalt oxide is 0.352 g/L) as compared to the bare electrodes (carbon felt is 0.22 g/L) tested, which was found to be in correspondence with the pH changes in the system. Electrochemical analysis revealed improved electrotrophy in the hybrid electrode, as confirmed by the increased redox current for the hybrid electrode as compared to plain electrodes. Cyclic voltammetry analysis also confirmed the role of the biocatalyst developed on the electrode in CO2 sequestration.

Four strains of bioflocculant-producing bacteria were isolated from a palm oil mill effluent (POME). The four bacterial strains were identified as Pseudomonas alcaliphila (B1), Pseudomonas oleovorans (B2), Pseudomonas chengduensis (B3), and Bacillus nitratireducens (B4) by molecular identification. Among the four bacterial strains, Bacillus nitratireducens (B4) achieved the highest flocculating activity (49.15%) towards kaolin clay suspension after eight hours of cultivation time and was selected for further studies. The optimum conditions for Eriochrome Black T (EBT) flocculation regarding initial pH, type of cation, and B4 dosage were determined to be pH 2, Ca2⁺ cations, and a dosage of 250 mL/L of nutrient broth containing B4. Under these conditions, above 90% of EBT dye removal was attained. Fourier transform infrared spectroscopic (FT-IR) analysis of the bioflocculant revealed the presence of hydroxyl, alkyl, carboxyl, and amino groups. This bioflocculant was demonstrated to possess a good flocculating activity, being a promissory, low-cost, harmless, and environmentally friendly alternative for the treatment of effluents contaminated with dyes.

A novel method of preparing reduced graphene oxide (RGOX) from graphene oxide (GOX) was developed employing vegetable extract, Chenopodium album, as a reducing and stabilizing agent. Chenopodium album is a green leafy vegetable with a low shelf life, fresh leaves of this vegetable are encouraged to be used due to high water content. The previously modified &lsquo, Hummers method&rsquo, has been in practice for the preparation of GOX by using precursor graphite powder. In this study, green synthesis of RGOX was functionally verified by employing FTIR and UV-visible spectroscopy, along with SEM and TEM. Our results demonstrated typical morphology of RGOX stacked in layers that appeared as silky, transparent, and rippled. The antibacterial activity was shown by analyzing minimal inhibitory concentration values, agar diffusion assay, fluorescence techniques. It showed enhanced antibacterial activity against Gram-positive and Gram-negative bacteria in comparison to GOX. It has also been shown that the synthesized compound exhibited enhanced antibiofilm activity as compared to its parent compound. The efficacy of RGOX and GOX has been demonstrated on a human breast cancer cell line, which suggested RGOX as a potential anticancer agent.

Batch desorption experiments of methylene blue (MB) dye from a clay adsorbent coating were carried out to evaluate the maximum desorption conditions. Combination of thermal and chemical regeneration techniques were used for the desorption process. The desorption of MB was found to be 70% using an HCl solvent after heating adsorbent coating at 160 &deg, C. The optimization study was carried out to identity the optimum desorption conditions using MINITAB 14 software. The individual and interaction effects of three factors, temperature, dye concentration and contact time for desorption of dye were determine by applying response surface methodology (RSM). The optimization results showed that all three factors have main effects whereas the interaction of concentration&ndash, time is significant as compared to other interactions. The findings exhibit a maximum desorption efficiency 23 mg/g at 60 &deg, C for 100 mg/L of dye and 150 min of contact time.