Predictive modeling of copper (II) adsorption from aqueous solutions by sawdust: a comparative analysis of adaptive neuro-fuzzy interference system (ANFIS) and artificial neural network (ANN) approaches.

Heavy metal ions are considered to be the most prevalent and toxic water contaminants. The objective of thois work was to investigate the effectiveness of employing the adsorption technique in a laboratory-size reactor to remove copper (II) ions from an aqueous medium. An adaptive neuro-fuzzy inference system (ANFIS) and a feed-forward artificial neural network (ANN) were used in this study. Four operational factors were chosen to examine their influence on the adsorption study: pH, contact duration, initial Cu (II) ions concentration, and adsorbent dosage. Using sawdust from wood, prediction models of copper (II) ions adsorption were optimized, created, and developed using the ANN and ANFIS models for tests. The result indicates that the determination coefficient for copper (II) metal ions in the training dataset was 0.987. Additionally, the ANFIS model's R2 value for both pollutants was 0.992. The findings demonstrate that the models presented a promising predictive approach that can be applied to successfully and accurately anticipate the simultaneous elimination of copper (II) and dye from the aqueous solution.

The mechanism of solid acid-catalyzed bamboo sawdust liquefaction under polyol systems.

Solid acid catalysts are widely used in the field of biomass catalytic conversion owing to their advantages of low environmental pollution, easy separation and reusability. Nevertheless, there are relatively few studies on the mechanism of solid acid liquefaction for biomass. In this study, the effect of acid strength and acid amount of various solid acids on the liquefaction efficiency has been investigated using waste bamboo sawdust generated from the pulp and paper industry as the raw material. In addition, the physicochemical changes of cellulose, hemicellulose and lignin during the reaction process of bamboo sawdust have been studied, and the liquefaction mechanism of bamboo sawdust under the action of various solid acids has been concluded. As a result, the liquefaction efficiency of bamboo sawdust under the polyol system of PEG400/propanetriol is mainly related to the acid strength of the solid acid, and the greater the acid strength of the solid acid, the better the catalytic effect on the bamboo sawdust, in which the residual amount of bamboo sawdust liquefaction catalyzed by the SPA catalyst is only 17.72%. Noteworthy, the most difficult component to liquefy is the crystallization of natural cellulose I into cellulose II during the reaction process, which is the primary obstacle to the complete liquefaction of bamboo sawdust by solid acid. Overall, these findings are valuable for the high value utilization of waste bamboo sawdust in the pulp and paper industry, as well as the application of solid acid catalytic technology for biomass.

Development and Characterisation of Composites Prepared from PHBV Compounded with Organic Waste Reinforcements, and Their Soil Biodegradation.

Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) is a biobased and biodegradable polymer. This polymer is considered promising, but it is also rather expensive. The objective of this study was to compound PHBV with three different organic fillers considered waste: human hair waste (HHW), sawdust (SD) and chitin from shrimp shells. Thus, the cost of the biopolymer is reduced, and, at the same time, waste materials are valorised into something useful. The composites prepared were characterised by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), tensile strength and scanning electron micrograph (SEM). Tests showed that chitin and HHW did not have a reinforcing effect on tensile strength while the SD increased the tensile strength at break to a certain degree. The biodegradation of the different composites was evaluated by a soil burial test for five months. The gravimetric test showed that neat PHBV was moderately degraded (about 5% weight loss) while reinforcing the polymer with organic waste clearly improved the biodegradation. The strongest biodegradation was achieved when the biopolymer was compounded with HHW (35% weight loss). The strong biodegradation of HHW was further demonstrated by characterisation by Fourier-transform infrared spectroscopy (FTIR) and solid-state nuclear magnetic resonance (NMR). Characterisation by SEM showed that the surfaces of the biodegraded samples were eroded.

Experimental investigation on the effect of blending bituminous coal with pinus sawdust on combustion performance parameters.

Combustion of bituminous coal and pinus sawdust blends was investigated experimentally within a drop tube furnace (DTF) with the aim of determining particle residence times and temperatures during the process. Evaluation of these parameters gives useful information to engineers who want to optimise the co-combustion process of coal and biomass blends. The DTF experimental approach was used to investigate fuel blends with a pinus sawdust mass substitution of 0, 10, 20, and 30% at different furnace temperatures of 1273, 1473 and 1673 K. Results showed that during stage 1 of the experimental setup which mimics devolatilisation, particle residence time at a distance of 520 mm from the injection point decreased from 0.8 to 0.7 s as blending by pinus sawdust increased from 0 to 30 %. During stage 2 of the experimental setup which mimics char combustion, particle residence time at a distance of 1320 mm from the injection point decreased from 3.9 to 2.0 s as blending by pinus sawdust increased from 0 to 30 %. The blending ratios under investigation demonstrated similar profiles of particle temperature at different furnace positions though further analysis showed that the highly blended samples required less time to attain high temperatures. By extension, since fuel blends with higher percentages of pinus sawdust were able to attain higher temperatures at shorter residence time, combustion intensity was deduced to increase with the blending ratio whilst stability decreased. As such, caution should be taken with materials used for furnace and burner design as high-temperature zones move backwards towards the injection point as blending increases.

Metabolomics-Based Analysis on the Effect and Metabolic Response of Mycelia by Sawdust Addition from Hypsizygus marmoreus.

The composition of culture substrate is an important environmental factor that affects the growth and metabolism of Hypsizygus marmoreus, and sawdust is commonly used as the substrate for cultivating mushrooms. However, the influences of sawdust on metabolic level of H. marmoreus in mycelial growth is little reported. In this study, the effect of sawdust addition on mycelial growth rate, morphological characteristics and nutrient content of H. marmoreus was explored, and the metabolic response was analyzed based on LC-MS/MS. The results showed the mycelial growth rates and the number of mycelial clamp connections in sawdust medium A and sawdust medium B were significantly higher than that of the basic medium (Control). The mycelial morphology in sawdust medium A was denser, with higher edge trimness and stronger aerial mycelia. The contents of crude fiber, crude protein and polysaccharide of the mycelia from sawdust medium A increased by 85.15%, 90.65% and 92.61%, respectively, compared to that in the basic medium. A total of 551 metabolites were identified and obtained. The differential accumulated metabolites (DAMs) were mainly amino acids, lipids compounds and carbohydrates. It was speculated that the addition of sawdust played a vital role in promoting the cell division and, thus, the formation of clamp connections in H. marmoreus mycelia. Regarding amino acids, the metabolism of glycine, serine and ABC transporters was active with the increase in sawdust, thereby increasing the protein content. And some valuable bioactive molecules were found, such as docosahexaenoic acid (DHA). This study will lay the foundation for further research on the substance transformation and quality improvement of cultivation substrate for mushrooms.

Sustainable cellulose foams for all-weather high-performance radiative cooling and building insulation.

Passive daytime radiative cooling (PDRC) as a zero-energy-consumption cooling technique offers rich opportunities in reducing global energy consumption and mitigating CO2 emissions. Developing high-performance PDRC coolers with practical applicability based on sustainable materials is of great significance, but remains a big challenge. Herein, polyvinyl alcohol (PVA) and esterified cellulose (EC) extracted from sawdust were used as raw materials to construct foams by using a dual-crosslinking assisted-unidirectional freeze-drying strategy followed by hydrophobic surface modification. The resultant PVA/EC (PEC) foams with ideal hierarchical macropore structure displayed various excellent features, such as low thermal conductivity (26.2 mW·m-1·K-1), high solar reflectance (95 %) and infrared emissivity (0.97), superhydrophobicity as well as high mechanical properties. The features allowed the PEC foams to be used as radiative coolers with excellent PDRC performance and thermal insulating materials. A maximum sub-ambient temperature drops of 10.2 °C could be achieved for optimal PEC foams. Building simulations indicated that PEC foams could save 55.8 % of the energy consumption for Xi'an. Our work would give inspiration for designing various types of PDRC coolers, including but certainly not limited to foams-based radiative coolers.

Drying characteristics of sewage sludge pre-conditioned by CaO and sawdust under low-temperature drying conditions.

Heat pump drying is a low-carbon method of sludge drying. The operating temperature of a heat pump is generally not more than 70℃. To improve the drying efficiency of heat pump dryers, the effects of air parameters and additives on sludge drying characteristics at low temperatures were studied. The sludge drying experiments were conducted at an air temperature 50-70℃ and an air velocity of 0.5-1.7 m/s. The experimental results showed that the increase of air temperature, velocity and the addition ratio of additives can accelerate the sludge drying process. The average and maximum drying rates of sludge pre-conditioned by CaO and sawdust increased by 14.23% and 25.71%, respectively, compared with those of pure sludge. The two-way analysis of variance (ANOVA) revealed that the influence of air temperature on the sludge drying was higher than that of air velocity. Five reference models were fitted by the drying experiment data. The Page model has the highest R2, so it is the most suitable model to predict the drying time of sludge at low temperatures.

Extraction of cellulose nanofibrils from pine sawdust by integrated chemical pretreatment.

Reducing energy consumption is major challenge in the industrialization of chemical pretreatments for the extraction of cellulose nanofibrils (CNF). In this study, an integrated chemical pretreatment with alkaline/acid-chlorite/TEMPO-oxidant was used for the nano-fibrillation of CNF from pine sawdust (WS). The alkaline and acid-chlorite pretreatments effectively eliminated the non-cellulosic components present in WS, resulting in the delamination of individual cell layers and swelling of the internal structures within the cellulose fiber bundles and cellulose microfibrils that form these layers. The spacing between CNF within the cellulose microfibrils increased from 3.7 nm to 5.5 nm. These loosely packed hierarchical structures facilitated the penetration of the reagent, which led to an increase in the specific surface area during the TEMPO-oxidant reaction and consequently accelerated the reaction rate. The WS was pretreated in a very dilute solution (1 % NaOH and 0.5 % NaClO2) under mild conditions (70 °C for 1 h), which resulted in a significant reduction of the TEMPO reaction time (from 3 h to 30 min) and a lower consumption of the reaction reagent (one fourth of the amount consumed compared to the direct oxidation of WS to achieve the same degree of cellulose nano-fibrillation).

Modeling and optimization of compaction pressure, binder percentage and retention time in the production process of carbonized sawdust-based biofuel briquettes using response surface methodology (RSM).

The importance of parameters such as compaction pressure, binder percentage and retention time and their interaction in the production of carbonized briquettes for domestic or industrial use cannot be overestimated, as they have a considerable impact on the properties of the resulting briquettes. This study used Box-Behnken Response Surface Methodology (RSM) and Analysis Of Variance (ANOVA) to show how the above parameters and their interactions significantly influence the Higher Heating Value (HHV), ash content and Impact Resistance Index (IRI) of the biofuels obtained. The briquettes are characterized in accordance with American Society for Testing and Materials ASTM D-(5865 and 3172). IRI is determined by the drop test. The Niton XLT900s X-ray fluorescence spectrometer is used for mineralogical analysis. The peel starch used as a binder is characterized by the Association of Official Agricultural Chemists standard. This starch has a starch purity of 89.8 %, an HHV of 13974 kJ/kg, a protein content of 4.79 % and a sugar content of 1.3 %. The HHV of the biofuels ranged from 23783 to 26050 kJ/kg, their ash content from 2.86 to 5.24 %, and the IRI from 136.36 to 500 %. The significant effect of binder on these results is confirmed (p < 0.05). The Standard deviations of ± 21.425 kJ/kg, ± 0.021 % and ± 2.121 % were obtained between the experimental values and those of the mathematical models developed to predict HHV, ash content and IRI. The optimum parameters for industrial biofuel production correspond to a binder percentage of 10 %, a compaction pressure of 75 kPa and a retention time of 7.49 min. The experimental results under these conditions are: 25596 kJ/kg, 3.01 % and 375 % for HHV, ash content and IRI. In correlation with the absence of certain heavy metals, the study confirms that the briquettes produced are suitable for domestic use.

Sequential catalytic lignin valorization and bioethanol production: an integrated biorefinery strategy.

BACKGROUND: The effective valorization of lignin and carbohydrates in lignocellulose matrix under the concept of biorefinery is a primary strategy to produce sustainable chemicals and fuels. Based on the reductive catalytic fractionation (RCF), lignin in lignocelluloses can be depolymerized into viscous oils, while the highly delignified pulps with high polysaccharides retention can be transformed into various chemicals. RESULTS: A biorefinery paradigm for sequentially valorization of the main components in poplar sawdust was constructed. In this process, the well-defined low-molecular-weight phenols and bioethanol were co-generated by tandem chemo-catalysis in the RCF stage and bio-catalysis in fermentation stage. In the RCF stage, hydrogen transfer reactions were conducted in one-pot process using Raney Ni as catalyst, while the isopropanol (2-PrOH) in the initial liquor was served as a hydrogen donor and the solvent for lignin dissolution. Results indicated the proportion of the 2-PrOH in the initial liquor of RCF influenced the chemical constitution and yield of the lignin oil, which also affected the characteristics of the pulps and the following bioethanol production. A 67.48 ± 0.44% delignification with 20.65 ± 0.31% of monolignols yield were realized when the 2-PrOH:H2O ratio in initial liquor was 7:3 (6.67 wt% of the catalyst loading, 200 °C for 3 h). The RCF pulp had higher carbohydrates retention (57.96 ± 2.78 wt%), which was converted to 21.61 ± 0.62 g/L of bioethanol with a yield of 0.429 ± 0.010 g/g in fermentation using an engineered S. cerevisiae strain. Based on the mass balance analysis, 104.4 g of ethanol and 206.5 g of lignin oil can be produced from 1000 g of the raw poplar sawdust. CONCLUSIONS: The main chemical components in poplar sawdust can be effectively transformed into lignin oil and bioethanol. The attractive results from the biorefinery process exhibit great promise for the production of valuable biofuels and chemicals from abundant lignocellulosic materials.

Comparison analysis of microbial agent and different compost material on microbial community and nitrogen transformation genes dynamic changes during pig manure compost.

This study aimed to assess the impact of microbial agent and different compost material, on physicochemical parameters dynamic change, nitrogen-transfer gene/bacterial community interaction network during the pig manure composting. Incorporating a microbial agent into rice straw-mushroom compost reduced the NH3 and total ammonia emissions by 25.52 % and 14.41 %, respectively. Notably, rice straw-mushroom with a microbial agent reduced the total ammonia emissions by 37.67 %. NH4+-N and pH emerged as primary factors of phylum-level and genus-level microorganisms. Microbial agent increased the expression of narG, nirK, and nosZ genes. Rice straw-mushroom elevated the content of amoA, nirK, nirS, and nosZ genes. Alcanivorax, Luteimonas, Pusillimonas, Lactobacillus, Aequorivita, Clostridium, Moheibacter and Truepera were identified as eight core microbial genera during the nitrogen conversion process. This study provides a strategy for reducing ammonia emissions and analyzes the potential mechanisms underlying compost processes.

Modeling Cu removal from aqueous solution using sawdust based on response surface methodology.

Copper (Cu), as one of the heavy metals widely used in industrial and agricultural activities, has a fundamental role in the pollution of water resources. Therefore, removing Cu from the aqueous solutions is considered an important challenge in the purification of water resources. Thus, in this study, sawdust with a diameter of 260-600 µm was used to remove Cu from the aqueous solutions. At first, sawdust was washed using distilled water and dried at laboratory temperature. Cu absorption experiments in closed conditions were performed based on the central composite design (CCD) model and with a range of initial Cu concentrations equal to 1-25 mgl-1. The amount of changes for other variables, including pH, time, and amount of sawdust, was equal to 2-10, 5-185 (min), and 5-25 (gl-1), respectively. After the completion of each test, the remaining Cu concentration in the solution was measured using atomic absorption, and the percentage of Cu removed was determined from the difference between the initial and final concentrations. The results showed that the CCD model has a favorable ability to predict Cu removal from the aqueous solutions (R2=0.90 and RSME=3.34%). Based on the Pareto analysis, contact time, the amount of sawdust, pH, and the Cu concentration had the most significant effect on removing Cu from the solution. Contact time, amount of sawdust, and pH were directly related, and the amount of dissolved Cu was proportional to the removal of Cu from the solution. Therefore, sawdust is desirable as a natural adsorbent, and the removal efficiency of Cu from solutions with low Cu concentration is very high (94%). In this regard, it is advised to use sawdust in the process of targeting Cu and heavy metals due to its low cost and availability.

The stabilisation of clayey soil by using sawdust and sawdust ash.

Soil stabilisation by waste materials has been recently employed to enhance soil engineering properties. The purpose of this study is to compare the impact of utilising sawdust in its raw form versus sawdust ash as a soil stabiliser. This is to determine if sawdust (SD) can be considered as a substitute for sawdust ash (SDA) in order to reduce incineration and air pollution. To fulfil this aim, the Atterberg limits, modified Proctor test, and Direct Shear test were performed on both stabilised and non-stabilised mixtures of clayey soil. The soil was treated with 2%, 5%, 8%, 12%, 15%, and 20% by soil dry weight of both SD and SDA. The findings show that the use of SD and SDA leads to a reduction in the plasticity index and the maximum dry unit weight of the soil while increasing its optimum moisture content. The bearing capacity of the soil was greatest at 5% for both SD and SDA, with SD exhibiting a greater enhancement (31.89%) than SDA. Therefore, it is recommended to utilise SD instead of SDA for soil stabilisation due to its superior effectiveness and less harmful environmental impact.

Bioprospecting CAZymes repertoire of Aspergillus fumigatus for eco-friendly value-added transformations of agro-forest biomass.

BACKGROUND: Valorizing waste residues is crucial to reaching sustainable development goals and shifting from a linear fossil-based economy to a circular economy. Fungal cell factories, due to their versatility and robustness, are instrumental in driving the bio-transformation of waste residues. The present work isolated a potent strain, i.e., Aspergillus fumigatus (ZS_AF), from an ancient Zloty Stok gold mine, which showcased distinctive capabilities for efficient hydrolytic enzyme production from lignocellulosic wastes. RESULTS: The present study optimized hydrolytic enzyme production (cellulases, xylanases, and ß-glucosidases) from pine sawdust (PSD) via solid-state fermentation using Aspergillus fumigatus (ZS_AF). The optimization, using response surface methodology (RSM), produced a twofold increase with maximal yields of 119.41 IU/gds for CMCase, 1232.23 IU/gds for xylanase, 63.19 IU/gds for ß-glucosidase, and 31.08 IU/gds for FPase. The secretome profiling validated the pivotal role of carbohydrate-active enzymes (CAZymes) and auxiliary enzymes in biomass valorization. A total of 77% of carbohydrate-active enzymes (CAZymes) were constituted by glycoside hydrolases (66%), carbohydrate esterases (9%), auxiliary activities (3%), and polysaccharide lyases (3%). The saccharification of pretreated wheat straw and PSD generated high reducing sugar yields of 675.36 mg/g and 410.15 mg/g, respectively. CONCLUSION: These findings highlight the significance of an efficient, synergistic, and cost-effective arsenal of fungal enzymes for lignocellulosic waste valorization and their potential to contribute to waste-to-wealth creation through solid-waste management. The utilization of Aspergillus fumigatus (ZS_AF) from an unconventional origin and optimization strategies embodies an innovative approach that holds the potential to propel current waste valorization methods forward, directing the paradigm toward improved efficiency and sustainability.

Robust and Multifunctional Ti3 C2 Tx /Modified Sawdust Composite Paper for Electromagnetic Interference Shielding and Wearable Thermal Management.

Robust, ultrathin, and environmental-friendliness papers that synergize high-efficiency electromagnetic interference (EMI) shielding, personal thermal management, and wearable heaters are essential for next-generation smart wearable devices. Herein, MXene nanocomposite paper with a nacre-like structure for EMI shielding and electrothermal/photothermal conversion is fabricated by vacuum filtration of Ti3 C2 Tx MXene and modified sawdust. The hydrogen bonding and highly oriented structure enhance the mechanical properties of the modified sawdust/MXene composite paper (SM paper). The SM paper with 50 wt% MXene content shows a strength of 23 MPa and a toughness of 13 MJ·M-3 . The conductivity of the SM paper is 10 195 S·m-1 , resulting in an EMI shielding effectiveness (SE) of 67.9 dB and a specific SE value (SSE/t) of 8486 dB·cm2 ·g-1 . In addition, the SM paper exhibits excellent thermal management performance including high light/electro-to-thermal conversion, rapid Joule heating and photothermal response, and sufficient heating stability. Notably, the SM paper exhibits low infrared emissivity and distinguished infrared stealth performance, camouflaging a high-temperature heater surface of 147-81 °C. The SM-based e-skin achieves visualization of Joule heating and realizes human motions monitoring. This work presents a new strategy for designing MXene-based wearable devices with great EMI shielding, artificial intelligence, and thermal management applications.

Effect of pyrolysis temperature and hydrothermal activation on structure, physicochemical, thermal and dye adsorption characteristics of the biocarbons.

In this study, the possibility of using sawdust from mixed woods to obtain biocarbons in the pyrolysis and steam activation using microwave radiation as an energy source was investigated. Biocarbons were characterized based on the results of N2 adsorption, thermogravimetric analysis (TGA), Fourier spectroscopy (ATR-FTIR), and Raman spectroscopy. Surface characterization was performed by Boehm titration and pHpzc determination. The adsorption capacity of methylene blue (MB) and methyl orange (MO) was studied. It was proved that the pyrolysis temperature and hydrothermal activation increased the biocarbons structural, surface and adsorption parameters of the obtained biocarbons. The amorphous materials of small specific surface area with a significant share of micropores were obtained. The steam activation resulted in significant development of the porous structure (to SBET =729.2 m2 /g and Vp =0.36 cm3 /g). The presence of functional groups, mainly phenolic ones, and pHpzc values indicating a potential for adsorption applications regarding MO and MB were found. The highest sorption capacity concerning MB (qe =122.8 mg/g) and MO (qe =99.1 mg/g) was observed for the steam-activated biocarbon BC-800MW . Using microwave energy hydrothermal activation proved very efficient, resulting in significant surface area and porosity development with a small loss of carbon matter.

Techno-economic analysis and environmental impact assessment of biodiesel production from bio-oil derived from microwave-assisted pyrolysis of pine sawdust.

Pyrolysis stands out as a highly promising technology for converting biomass. Upgrading the bio-oil to meet the requirements for fuelling internal combustion engines is indispensable. This study evaluates the economic viability of microwave-assisted pyrolysis (MAP) of pine sawdust, followed by bio-oil esterification for the production of biodiesel. Aspen Plus® was used to simulate a facility that processed 2000 metric tonnes of pine sawdust per day. The minimum fuel selling price (MFSP) of biodiesel was established through the use of a discounted cash flow analysis. A life cycle assessment approach was used to evaluate the environmental impact assessment of biodiesel production. Process modelling findings revealed that the pyrolysis section yielded 65.8 wt% bio-oil, 8.9 wt% biochar, and 25.3 wt% NCGs. The biodiesel product yield was 48 wt% of the raw bio-oil, yielding 631.7 tonnes per day of biodiesel. With the cost of methanol playing a significant role, the overall capital investment was $286.1 MM and the total yearly operating expenses were $164.9 MM. The predicted MFSP for biodiesel is $2.31/L, with yearly operational expenses and biodiesel output being the most important factors. The emission from the biodiesel production process resulted in a global warming potential of 70.97 kg CO2eq. With an anticipated MFSP that is competitive with traditional diesel fuel, the study concludes that the method is economically viable. The results underline how crucial it is to optimize crucial process variables in order to increase the process's economic viability.

Biodegradation of Petroleum Sludge by Methylobacterium sp. Strain ZASH.

A bacterium was isolated from sludge-contaminated soil in a petroleum refinery and tested for its ability to degrade aliphatic hydrocarbon compounds present in petroleum sludge. The isolate was grown on minimal salt media agar supplemented with 1% (w/v) petroleum sludge. The isolate was tentatively identified as Methylobacterium s p. s t rain ZASH based on the partial 16s rDNA molecular phylogeny. The bacterium grew optimally between the temperatures of 30°C and 35°C, pH 7 and 7.5, 0.5% and 1.5% (v/v) Tween 80 as the surfactant, and between 1% and 2% (w/v) peptone as the nitrogen source. The constants derived from the Haldane equation were µmax = 0.039 hr-1, Ks = 0.385% (w/v) total petroleum hydrocarbons (TPH) or 3,850 mg/L TPH, and Ki =1.12% (w/v) TPH or 11,200 mg/L. The maximum biodegradation rate exhibited by this strain was 19 mg/L/hr at an initial TPH concentration of 10,000 mg/L. Gas chromatography analysis revealed that after 15 days the strain was able to degrade all aliphatic n-alkanes investigated with different efficiencies. Shorter n-alkanes were generally degraded more rapidly than longer n-alkanes with 90% removal for C-12 compared to only 30% removal for C-36. The addition of sawdust did not improve bacterial degradation of petroleum hydrocarbons, but it assisted in the removal of remaining undegraded hydrocarbons through adsorption.

Synthesis of a Magnetic Nanostructured Composite Sorbent Only from Waste Materials.

Water pollution is a big problem for the environment, and thus depollution, especially by adsorption processes, has garnered a lot of interest in research over the last decades. Since sorbents would be used in large quantities, ideally, they should be cheaply prepared in scalable reactions from waste materials or renewable sources and be reusable. Herein, we describe a novel preparation of a range of magnetic sorbents only from waste materials (sawdust and iron mud) and their performance in the adsorption of several dyes (methylene blue, crystal violet, fast green FCF, and congo red). The preparation is performed in a hydrothermal process and is thus easily scalable and requires little sophisticated equipment. The magnetic nanostructured materials were analyzed using FTIR, VSM, SEM/EDX, XRD, and XPS. For crystal violet as a pollutant, more in-depth adsorption studies were performed. It was found that the best-performing magnetic sorbent had a maximum sorption capacity of 97.9 mg/g for crystal violet (methylene blue: 149.8 mg/g, fast green FCF: 52.2 mg/g, congo red: 10.5 mg/g), could be reused several times without drastic changes in sorption behavior, and was easily separable from the solution by simply applying a magnet. It is thus envisioned to be used for depollution in industrial/environmental applications, especially for cationic dyes.

Statistical Design and Optimization of Cr (VI) Adsorption onto Native and HNO3/NaOH Activated Cedar Sawdust Using AAS and a Response Surface Methodology (RSM).

The removal of heavy metals from wastewater has become the subject of considerable interest at present. Thus, the use of novel adsorbents that are highly efficient is of critical importance for the removal of Cr (VI) ions from aqueous media. The adsorption of Cr (VI) ions from aqueous solutions by a new adsorbent, cedar wood sawdust, and the optimization of its adsorption parameters, were investigated in this study. Cedar wood sawdust was used in its native and HNO3/NaOH chemically modified forms as new low-cost sorbents to remove Cr (VI) ions from aqueous solutions in a batch system. The adsorption conditions were analyzed via response surface methodology. The RSM results showed that the optimal adsorption conditions yielding the best response were an adsorbent mass of 2 g for native Cedar and 1.125 g for its activated form, a metal concentration of 150 mg/L for native Cedar and 250 mg/L for activated, a temperature of 50 °C, a pH of 1, and a contact time of 67.5 min. At optimum adsorption conditions, the maximum adsorption capacities and the adsorption yields were 23.64 mg/g and 84% for native Cedar and 48.31 mg/g and 99% for activated Cedar, respectively.