جستجوی مقالات مرتبط با کلیدواژه « Pyrolysis » در نشریات گروه « اکولوژی »

Poor management of chicken litter by the poultry industry has caused many environmental issues. Biochar’s unique characteristics make poultry litter-to-biochar conversion an intriguing management option thus, could be utilized as an organic fertilizer for plant nutrients. In this research, poultry litter was converted into biochar, which offers a range of possible applications, including analyzing key nutrients, improving air and water quality, conditioning soil, and neutralizing acidic soils. Fresh poultry litter was pyrolyzed for 20 minutes at a temperature of 500 oC in an oxygen-restricted muffle furnace to produce biochar. The biochar was examined chemically and physically using a variety of techniques. These included microwave plasma atomic emission spectroscopy (MP-AES), the scanning electron microscope (SEM), the Fourier transform infrared (FTIR) spectroscopy, and thermo gravimetric analysis (TGA and DTG). The pyrolysis output was 56.38%, 32.20% ash, 2.00% moisture, 0.60 kg/m3 bulk density, pH 9.65, and 0.00314 dS/m EC. The mineral elemental analysis gave 621.73 mg/kg calcium, 63.65 mg/kg potassium, 48.94 mg/kg magnesium, 13.14 mg/kg sodium, and 11.85 mg/kg phosphorus.  FTIR showed the presence of functional groups which could act as cation adsorbents. SEM pictures showed the sample’s amorphous, non-uniform surface. TGA and DTG curves showed mass loss and sample breakdown as the temperature climbed. Poultry litter converted to biochar can act as a nutrient-rich soil conditioner to address mineral deficits in fruits and vegetables grown in acidic soils. This is a good way to recycle agricultural trash.

Purpose:

 The role of cocoa pod husk waste in soil cadmium contamination has been largely overlooked. Hence, this study aims to provide a strategy for the management of cocoa pod husk waste when representing a pollution menace for cocoa plantations.

Method:

 Cocoa pod husks waste was subjected to composting and pyrolysis for decreasing the heavy metal content. Biochar and compost were characterized using SEM-EDS, and FTIR-ATR. Macro and micronutrients (Mg, K, Zn, Fe, Cu, Zn, Mn, and Na), and Cd were measured by atomic absorption spectroscopy (AAS). Sorption experiments and soil incubation experiments for two months were also carried out looking for an application of CPH materials in Cd sorption and remediation.

Results:

 Pyrolysis showed more effectiveness for Cd reduction in cocoa pod husk waste (90%) than composting (66%), 700 ℃ was the optimal temperature. Equilibrium isotherm experiments showed maximum Cd adsorption of 21.58 mg g-1 for Bc700 in solution. Biochar showed a small reduction of available Cd in naturally contaminated soil. Both materials have the potential to be used as organic fertilizer because of their high nutrient contents.

Conclusion:

 Biochar is an alternative to compost for the management of post-harvest cocoa wastes contaminated with Cd.

Crop wastes are underused organic resources due to low heating value and slow decomposition rates. However, conversion to biochar through pyrolysis could offer agronomic and environmental benefits. The study compared the pyrolysis of biochar from crop wastes, assessed their physicochemical properties for the purposeful use to improve soil fertility, crop productivity and their carbon sequestration potential. Biochar was produced from crop wastes such as cassava residues, corncobs, rice husk, sawdust, coffee husk, and peanut using an Elsa barrel pyrolyser. Standard laboratory procedures were used to analyze pH, CEC, total carbon and nitrogen and exchangeable cations. The biochars were high in nutrients containing 4.17–18.15 g kg−1 N, 22.26–42.51 mg kg−1 P, 2.48–4.18 cmol kg−1 K and pH 7.78–10.81 units. It is evident that adding biochar to acidic soil containing 0.79 g kg−1 N, 7.41 mg kg−1 P, 1.42 cmol kg−1 K and pH of 5.68 could increase soil fertility and plant productivity. Carbon dioxide reduction potential ranged from 94.46 to 313.42 CO2 eq kg−1. This implies that the concept and technique of producing biochar could be a valuable way of reducing carbon emissions into the atmosphere thereby mitigating climate change. Crop wastes and by-products which constitute a nuisance could be used to produce a very useful by-product, biochar whose quality depends on the substrate from which it is produced. Recycling crop wastes to biochar is strongly recommended to smallholder farmers for use in agriculture to improve fertility and crop productivity due to their high nutrient content and soil fertility attributes.

This research aimed to study the adsorption of ammonium and nitrate by simply modifying the surface of the rice husk using slow pyrolysis and surfactants modification.

Rice husk biochar was prepared by slowly pyrolyzing at 500 °C, 2 h. The rice husk and its biochar were modified by cetyltrimethylammonium bromide or sodium dodecylbenzenesulfonate. FTIR, BET and zeta potential measurements were used to characterize the obtained adsorbents.

Slow pyrolysis increased the specific surface area and decreased the surface charge of rice husk while surfactant clogged the pore but could change the charge of a surface. Adsorption of both ammonium and nitrate on rice husk, its biochar, and their modification with surfactants fitted Freundlich and Langmuir isotherms, indicating heterogeneity in adsorption. Slow pyrolysis gave the highest ammonium removal with maximum adsorption capacity of 44 mgN/g and it was a physical process. The cetyltrimethylammonium bromide modification gave a significant nitrate removal on both rice husk and its biochar with maximum adsorption of 278 and 213 mgN/g, respectively, which is higher than a commercial adsorbent.

These two modification techniques gave great adsorption enhancement with cost-effectiveness as compared to other reviewed methods which could use as a nitrogen-rich fertilizer and fertilizer retainment in crop production.