This study reports the extraction of cellulose by means of an environment-friendly multistep procedure involving alkaline treatment and totally chlorine-free bleaching. The multistep process begins with the removal of pectin, cutin, waxes, and other extractives from Eucalyptus lenceolata straw, followed by the removal of hemicelluloses and lignin using an alkaline treatment, and lastly by further delignification of the cellulose pulp through a two-step bleaching process, first with the use of hydrogen peroxide/tetraacetylethylenediamine (TAED) and then with the use of a mixture of acetic and nitric acids. The Eucalyptus lenceolata samples were collected from the mountains of the Malakand division of Khyber Pakhtunkhwa, Pakistan and were ground into smaller particles. The pulp resulting from each step was characterized by infrared spectroscopy (ATR-FTIR) to detect structural changes. The purified cellulose was characterized through different analytical techniques such as Fourier transfer infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and scanning electron microscopy (SEM). The isolated cellulose has a high degree of purity and crystallinity (73%) and thermal stability as verified by XRD and TGA, respectively. SEM was used to study the surface morphology of cellulose, indicating that the surface was free from lignin and hemicelluloses due to the chemical treatment. This study indicates that the multistep procedure is quite adequate for the extraction of cellulose.

The pyrolysis process of coconut residue and the activated carbon was investigated using thermogravimetric analysis in the range of 25 to 900 °C, with three altered heating rates: 3, 5, and 10 °C/min. The results of the thermal decomposition showed that it occurred in three distinct phases: dehydration, active pyrolysis, and passive pyrolysis. The derivative thermogravimetric analysis indicated that increasing the heating rate led to a shift in the maximum weight loss rate towards higher temperatures. To better understand the kinetics constraints, the Coats–Redfern method was applied to determine the activation energy (Ea) and the frequency factor (A). The activation energies for the pyrolysis process varied between 159.57 and 177.45 kJ/mol for RCR and from 132.62 to 147.1 kJ/mol for ACCR at different heating rates. Additionally, the physical properties of the samples were investigated using techniques like scanning electron microscopy and the Brunauer–Emmett–Teller surface analysis. The findings of the study demonstrated that the activation energies of the activated carbon were lower than those of the original biomass. Furthermore, the activation energy values achieved from the D1–D4 models were considered reliable, indicating that the D model was more suitable compared to other models for describing the pyrolysis process and predicting its kinetics.

In the present study, we determined the levels of chlorinated pesticide residues in surface water samples collected from the Charsadda district (KPK, Pakistan). SPME-GC-ECD with COMBI PAL CTC autosampler was used for extraction and analysis of 20 organochlorine pesticides in the collected water samples. For maximum efficiency of the SPME procedure, several parameters were studied, including the extraction and desorption time of the fiber, solution pH, agitation of samples, and stirring speed, etc. This method showed good liner response, with R² values in the range of 0.9887 to 0.9999 for all pesticides. This method also provided good percent recoveries at 1 µg L⁻¹ (87.5 to 106.0%) and at 2 µg L⁻¹ (88.5 to 109.2%). Lower limits of detection for all 20 chlorinated pesticides were found to be lower than their maximum permissible contamination levels. Approximately 50% of the surface water samples collected from the Charsadda district were found to be contaminated with the pesticides γ-BHC, heptachlor, aldrin and dieldrin, with maximum concentrations of 0.023, 0.108, 0.014 and 0.013 µg L⁻¹, respectively. For adults and children, the cancer risk from water due to contamination by various pesticides ranged from 0 to 33.29 × 10⁻⁶. The non-carcinogenic risk from each pollutant in the water samples of the Charsadda district was found to be in the order of heptachlor > aldrin > dieldrin > γ-BHC. However, the pesticides α-BHC, β-BHC, heptachlor epoxide, chlordane, endrin, 4,4′-DDD, endrin ketone, 4,4′-DDT, endosulfan sulfate and methoxychlor were not detected in any of the surface water samples of investigated in the present study.

Environmental friendly method for the extraction of cellulose from Triflolium resopinatum and its characterization

The gasification kinetics of pellets obtained from organic solid wastes (OWS) and raw materials were studied using the Coats–Redfern and DAEM methods. The different methods were comparatively analyzed for mutual verification, and the similar activation energies obtained by each method affirmed the accuracy of the kinetics calculation. Overall, the activation energies of the char gasification stage ranged from 200 to 265 kJ mol⁻¹, higher than those of the devolatilization stage, which ranged from 130 to 200 kJ mol⁻¹ for all pellets and raw materials. During the devolatilization stage, the activation energies of the pellets were invariably higher than those of their corresponding raw materials, which was the opposite for the char gasification stage. A detailed comparison between the calculation results from the Coats–Redfern and DAEM methods confirmed that the devolatilization stage is controlled by one-dimensional diffusion, and the gasification stage is controlled by two-dimensional or three-dimensional diffusion for pellets and raw materials.