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Oligo(L-lactic acid) (OLLA) was synthesized by ring opening polymerization of L-lactides using stannous octoate (0.03 wt% of lactide). While this served as the initiator, L-lactic acids were the co-initiators at 140 °C for 10 h, wherein L-lactic acids were prepared by hydrolytic degradation of L-lactides at 100 °C for 1 h. The molecular weight or degree of polymerization was controlled with monomer/co-initiator ratio (mol/mol). α-cellulose and microcrystalline cellulose (MCC) were extracted from jute fiber by subsequent treatment with sodium chlorite (Na2ClO2), NaOH and H2SO4. Grafting of OLLA onto α-cellulose and MCC in toluene was carried out using para-toluene sulphonic acid as a catalyst and potassium persulphate (KPS) as an initiator at 130 °C under 380 mm (Hg) pressure for 3, 6, 9, 12, 15, and 18 h. New properties of α-cellulose and MCC were observed due to the successful grafting onto α-cellulose and MCC. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscope (SEM) were conducted in order to confirm grafting of OLLA onto cellulose and MCC. The FTIR analysis results showed there are some new characteristic absorption peaks appeared (1728 to 1732 cm−1) in the spectrum, which confirmed the grafting of OLLA onto α-cellulose and MCC was successful. SEM images of α-cellulose and MCC before and after grafting revealed significant changes in surface morphology. Grafting of MCC could be more effective for further application in comparison to α-cellulose.

This research addresses the challenge of determining the optimal parameters for the selective laser sintering (SLS) process using thermoplastic polyurethane elastomer (TPU) flexa black powder to achieve high-quality SLS parts. This study focuses on two key printing process parameters, namely layer thickness and the laser power ratio, and evaluates their impact on four output responses: density, hardness, modulus of elasticity, and time required to produce the parts. The primary impacts and correlations of the input factors on the output responses are evaluated using response surface methodology (RSM). A particular response optimizer is used to find the optimal settings of input variables. Additionally, the rationality of the model is verified through an analysis of variance (ANOVA). The research identifies the optimal combination of process parameters as follows: a 0.11 mm layer thickness and a 1.00 laser power ratio. The corresponding predicted values of the four responses are 152.63 min, 96.96 Shore-A, 2.09 MPa, and 1.12 g/cm3 for printing time, hardness, modulus of elasticity, and density, respectively. These responses demonstrate a compatibility of 66.70% with the objective function. An experimental validation of the predicted values was conducted and the actual values obtained for printing time, hardness, modulus of elasticity, and density at the predicted input process parameters are 159.837 min, 100 Shore-A, 2.17 MPa, and 1.153 g/cm3, respectively. The errors between the predicted and experimental values for each response (time, hardness, modulus of elasticity, and density) were found to be 4.51%, 3.04%, 3.69%, and 2.69%, respectively. These errors are all below 5%, indicating the adequacy of the model. This study also comprehensively describes the influence of process parameters on the responses, which can be helpful for researchers and industry practitioners in setting process parameters of similar SLS operations.

Biodegradable and eco-friendly composite adsorbent was synthesized from modified jute fiber and gelatin and evaluated its efficacy in removing cadmium (Cd2+), lead (Pb2+), and chromium (Cr3+) ions from an aqueous solution. The prepared sample was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray analyses, which revealed that gelatin successfully intercalated into the microcrystalline cellulose matrix. In batch adsorption studies, the effects of pH, adsorbent dosage, initial metal ions concentration, and temperature on the removal of heavy metal ions were investigated. The adsorption capacity of the composite varied with changing parameters, and the maximum removal efficiency obtained for Cd2+, Pb2+, and Cr3+ was 95%, 88%, and 70%, respectively, at pH 6 with 60 ppm of each metal ions concentration and an adsorbent dosage of 1.0 g L−1. Different functional groups in composite adsorbent facilitated heavy metal ions adsorption. Five error analysis methods were used to evaluate the fit the goodness of the data. The equilibrium adsorption and kinetic data were well-fitted with the Langmuir isotherm model and pseudo-second-order, respectively. Moreover, the thermodynamic study showed that the adsorption was spontaneous, chemisorption, and endothermic. Our work offers a sustainable and biodegradable composite synthesized from modified jute fiber and gelatin for multimetal ions removal from an aqueous, which is an eco-friendly alternative to conventional nonbiodegradable adsorbents with potential environmental risks.

A breakthrough in superabsorbent hydrogel (SAH) preparation was studied in the current issue by blending potato starch and acrylic acid for wastewater treatment. Gamma irradiation source (60Co irradiation) was used to irradiate SAH from 1 to 10 kGy dose at room temperature (~27°C). The swelling ratio, water absorption, equilibrium water content, and gel fraction properties of the hydrogel were investigated. The as-prepared hydrogel treated with KOH (THG) showed excellent absorption capacity but less mechanical stability compared to untreated hydrogel (UHG). The gel fraction of treated SAH was slightly lower in methanol, but the utmost in water at 5 kGy infers the proper grafting of SAH at this point. The prepared SAH was characterized using scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) to investigate the surface morphology and molecular interaction, respectively. Moreover, this study’s focal point is to propose an alternative method to remove chromium and methylene blue by SAH from industrial wastewater. The Cr adsorption capacity of UHG was higher than that of THG because the proton’s replacement is easier than that of K by Cr. On the other hand, THG was found to be more efficient in removing methylene blue from industrial wastewater due to the presence of an easily ionized group (–COOK) in SAH. Therefore, the hydrogel can be proposed as a potential superabsorbent to remove heavy metals and organic dyes from industrial wastewater.

Neisseria meningitidis is a commensal pathogen that causes infectious cerebrospinal disease in people of all ages. The multivariate role of six disease-causing polysaccharide serotypes is found to play a crucial role in developing vaccines (or general treatment strategies) to treat this emerging pathogen. Iron is a crucial transition metal for N. meningitidis. Proteomic analysis data could be valuable for vaccine design. Here, we conduct a comparative study using computational bioinformatic tools to identify the most effective iron-regulated outer membrane proteins (OMPs) as immunogenic targets for a potential vaccine against N. meningitidis. The basic properties of N. meningitidis OMPs are explored for flexibility, solubility, hydrophilicity, beta-turns, and overall antigenic probability. Results of our study suggest that iron-regulated OMPs are flexible and soluble in water with high densities of conformational B-cell epitopes. As such, they can be recommended as a novel candidate for a vaccine against N. meningitidis both in vitro and in vivo.