Removal of Cr(VI) from Wastewater Using Acrylonitrile Grafted Cellulose Extracted from Sugarcane Bagasse.

A highly efficient low-cost adsorbent was prepared using raw and chemically modified cellulose isolated from sugarcane bagasse for decontamination of Cr(VI) from wastewater. First, cellulose pulp was isolated from sugarcane bagasse by subjecting it to acid hydrolysis, alkaline hydrolysis and bleaching with sodium chlorate (NaClO3). Then, the bleached cellulose pulp was chemically modified with acrylonitrile monomer in the presence Fenton's reagent (Fe+2/H2O2) to carry out grafting of acrylonitrile onto cellulose by atom transfer radical polymerization. The developed adsorbent (acrylonitrile grafted cellulose) was analyzed by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Both raw cellulose and acrylonitrile grafted cellulose were used for chromium removal from wastewater. The effects of metal ion concentration, pH, adsorbent dose and time were studied, and their values were optimized. The optimum conditions for the adsorption of Cr(VI) onto raw and chemically modified cellulose were: metal ion concentration: 50 ppm, adsorbent dose: 1 g, pH: 6, and time: 60 min. The maximum efficiencies of 73% and 94% and adsorption capacities of 125.95 mg/g and 267.93 mg/g were achieved for raw and acrylonitrile grafted cellulose, respectively. High removal efficiency was achieved, owing to high surface area of 79.92 m2/g and functional active binding cites on grafted cellulose. Isotherm and kinetics studies show that the experimental data were fully fitted by the Freundlich isotherm model and pseudo first-order model. The adsorbent (acrylonitrile grafted cellulose) was regenerated using three different types of regenerating reagents and reused thirty times, and there was negligible decrease (19%) in removal efficiency after using it for 30 times. Hence, it is anticipated that acrylonitrile could be utilized as potential candidate material for commercial scale Cr(VI) removal from wastewater.

Efficient Removal of Hexavalent Chromium (Cr(VI)) from Wastewater Using Amide-Modified Biochar.

The utilization of biochar, derived from agricultural waste, has garnered attention as a valuable material for enhancing soil properties and serving as a substitute adsorbent for the elimination of hazardous heavy metals and organic contaminants from wastewater. In the present investigation, amide-modified biochar was synthesized via low-temperature pyrolysis of rice husk and was harnessed for the removal of Cr(VI) from wastewater. The resultant biochar was treated with 1-[3-(trimethoxysilyl) propyl] urea to incorporate an amide group. The amide-modified biochar was characterized by employing Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) techniques. During batch experiments, the effect of various parameters, such as adsorbent dosage, metal concentration, time duration, and pH, on Cr(VI) removal was investigated. The optimal conditions for achieving maximum adsorption of Cr(VI) were observed at a pH 2, an adsorbent time of 60 min, an adsorbent dosage of 2 g/L, and a metal concentration of 100 mg/L. The percent removal efficiency of 97% was recorded for the removal of Cr(VI) under optimal conditions using amide-modified biochar. Freundlich, Langmuir, and Temkin isotherm models were utilized to calculate the adsorption data and determine the optimal fitting model. It was found that the adsorption data fitted well with the Langmuir isotherm model. A kinetics study revealed that the Cr(VI) adsorption onto ABC followed a pseudo-second-order kinetic model. The findings of this study indicate that amide-functionalized biochar has the potential to serve as an economically viable substitute adsorbent for the efficient removal of Cr(VI) from wastewater.

Therapeutic Potential of Selected Medicinal Plant Extracts against Multi-Drug Resistant Salmonella enterica serovar Typhi.

Salmonella enterica serovar Typhi is Gram negative, rod shaped, facultative anaerobic bacterium, belongs to enterobacteriaceae family that causes typhoid fever in humans. This bacterium has become a super bug due to acquisition of multi drug resistance. Bacteria is transmitted through food and water contaminated with human feaces. Present study reports the screening of Adhatoda vasica, Amaranthus hybridus and Aloe barbadensis and their evaluation against multi-drug resistant Salmonella enterica serovar Typhi. Qualitative analysis of ten phytochemicals was conducted using chemical method and Gas Chromatography-Mass Spectrometry (GCMS). Antibacterial activity of plants was carried out by agar well diffusion method on Mueller Hinton agar. Total tannins, total alkaloids and total flavonoids of different parts of three plants were estimated through spectrophotometer. Total tannins content in different parts of plants was present in the given order Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Adhatoda vasica flower > Adhatoda vasica stem. Whereas, the order of total flavonoid concentration was Amaranthus hybridus leaf > Aloe barbadensis leaf > Adhatoda vasica leaf > Amaranthus hybridus seed. Total alkaloids have order, Adhatoda vasica leaf > Amaranthus hybridus leaf > Adhatoda vasica flower > Amaranthus hybridus seed > Aloe barbadensis leaf. Results of phytochemical analysis suggested that plants have strong profile of antioxidants, total phenolic contents and various enzymes proposing them best alternate to cure bacterial infections. GC-MS analysis further confirmed stronger phytochemical profile that can be utilized as antagonists to Salmonella enterica serovar Typhi.

Efficient Removal of Pb(II) from Aqueous Medium Using Chemically Modified Silica Monolith.

The adsorptive removal of lead (II) from aqueous medium was carried out by chemically modified silica monolith particles. Porous silica monolith particles were prepared by the sol-gel method and their surface modification was carried out using trimethoxy silyl propyl urea (TSPU) to prepare inorganic-organic hybrid adsorbent. The resultant adsorbent was evaluated for the removal of lead (Pb) from aqueous medium. The effect of pH, adsorbent dose, metal ion concentration and adsorption time was determined. It was found that the optimum conditions for adsorption of lead (Pb) were pH 5, adsorbent dose of 0.4 g/L, Pb(II) ions concentration of 500 mg/L and adsorption time of 1 h. The adsorbent chemically modified SM was characterized by scanning electron microscopy (SEM), BET/BJH and thermo gravimetric analysis (TGA). The percent adsorption of Pb(II) onto chemically modified silica monolith particles was 98%. An isotherm study showed that the adsorption data of Pb(II) onto chemically modified SM was fully fitted with the Freundlich and Langmuir isotherm models. It was found from kinetic study that the adsorption of Pb(II) followed a pseudo second-order model. Moreover, thermodynamic study suggests that the adsorption of Pb(II) is spontaneous and exothermic. The adsorption capacity of chemically modified SM for Pb(II) ions was 792 mg/g which is quite high as compared to the traditional adsorbents. The adsorbent chemically modified SM was regenerated, used again three times for the adsorption of Pb(II) ions and it was found that the adsorption capacity of the regenerated adsorbent was only dropped by 7%. Due to high adsorption capacity chemically modified silica monolith particles could be used as an effective adsorbent for the removal of heavy metals from wastewater.

Mechanism of rice bran lipase inhibition through fermentation activity of probiotic bacteria.

Rice bran oil is known as wonder oil and it is the most important vegetable oil in Asia. Rice bran oil is extracted from bran that is the outer hard layer of rice. It is an emerging category in edible oil with a lot of nutritional properties and health benefits. Rice bran oil is heart-friendly, boosts up immunity, and prevents from other diseases occurring commonly in Pakistan. The current study aimed to stabilize rice bran oil through different probiotic isolates and to assess the nutritional content of rice bran oil after stabilization. The study was aimed to inactivate naturally occurring lipases that can hydrolyze oil into glycerol and free fatty acid which is a serious problem that gives it a rancid taste and smell. Antilipase activity was used to inactivate naturally occurring lipases that are a huge threat to the stabilization process. The fermentation process utilizes antilipase activity without affecting the nutritional value of oil. Lactobacillus strains were used for the stabilization of rice bran oil. Rice bran oil was extracted in the Soxhlet apparatus. The probiotic lab isolates Lactobacillus delbrueckii S2, Lactobacillus casei S5 and Lactobacillus plantarum S13 were applied to it to increase its shelf life and prevent oxidative rancidity. The extraction temperature of rice bran oil was maintained above 40 °C to inhibit lipase activity. Rice bran oil samples were stored at refrigeration temperature to arrest lipase activity. Probiotics maintained acidic pH to keep oil stabilization. Qualitative analysis was done to confirm rice bran oil stabilization. Determination of Free Fatty Acid (FFA) and saponification value confirmed that oxidative rancidity of rice bran oil was controlled by probiotics. FFA count was less than 10% and Saponification Value (SV) was 180. GC analysis was performed to analyze the FFA profile. Gas Chromatography results have shown 3 fatty acids. Statistical analysis has shown non-significant effect on different incubation temperatures of Lactobacillus isolates. Among the biological methods of stabilization, the use of probiotics is a novel concept and recommended for commercial application.

Removal of potentially toxic elements from aqueous solutions and industrial wastewater using activated carbon.

Water contamination with potentially toxic elements (PTEs) has become one of the key issues in recent years that threatens human health and ecological systems. The present study is aimed at removing PTEs like cadmium (Cd), chromium (Cr), copper (Cu) and lead (Pb) from aqueous solutions and industrial wastewater using activated carbon (AC) as an adsorbent through different batch and column experiments. Results demonstrated that the removal of PTEs from aqueous solutions was highly pH dependent, except for Cr, and the maximum removal (>78%) was recorded at pH 6.0. However, maximum Cr removal (82.8%) was observed at pH 3.0. The adsorption reached equilibrium after 60 min with 2 g of adsorbent. Coefficient (R2) values suggested by the Langmuir isotherm model were 0.97, 0.96, 0.93 and 0.95 for Cd, Cr, Cu and Pb, respectively, indicating the fit to this model. In column experiments, the maximum removal of PTEs was observed at an adsorbent bed height of 20 cm with the optimal flow rate of 3.56 mL/min. Furthermore, PTEs removal by AC was observed in the order of Cu > Cd > Pb > Cr. Findings from this study suggest that AC could be used as a promising adsorbent for simultaneously removing several PTEs from wastewaters.

Wild plant assessment for heavy metal phytoremediation potential along the mafic and ultramafic terrain in northern Pakistan.

This study investigates the wild plant species for their phytoremediation potential of macro and trace metals (MTM). For this purpose, soil and wild plant species samples were collected along mafic and ultramafic terrain in the Jijal, Dubair, and Alpuri areas of Kohistan region, northern Pakistan. These samples were analyzed for the concentrations of MTM (Na, K, Ca, Mg, Fe, Mn, Pb, Zn, Cd, Cu, Cr, Ni, and Co) using atomic absorption spectrometer (AAS-PEA-700). Soil showed significant (P < .001) contamination level, while plants had greater variability in metal uptake from the contaminated sites. Plant species such as Selaginella jacquemontii, Rumex hastatus, and Plectranthus rugosus showed multifold enrichment factor (EF) of Fe, Mn, Cr, Ni, and Co as compared to background area. Results revealed that these wild plant species have the ability to uptake and accumulate higher metals concentration. Therefore, these plant species may be used for phytoremediation of metals contaminated soil. However, higher MTM concentrations in the wild plant species could cause environmental hazards in the study area, as selected metals (Fe, Mn, Cr, Ni, Co, and Pb) have toxicological concerns.