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In this study, nickel-loaded perovskite oxides catalysts were synthesized via the impregnation of 10%Ni on XTiO

Present study evaluated the catalytic steam gasification of furniture waste to enhance the biohydrogen production. To do this, 10 wt% nickel loaded catalysts on the variety of supports (Al2O3, CeO2, CeO2-La2O3, and CeO2–ZrO2) were prepared by the novel solvent deficient method. The hydrogen selectivity (vol%) order of the catalysts was achieved as Ni/CeO2–ZrO2>Ni/CeO2>Ni/Al2O3≃Ni/CeO2-La2O3. The best catalytic activity of Ni/CeO2–ZrO2 catalyst (~82 vol % H2 at 800 °C) was ascribed to the smaller size of nickel crystals, finely dispersed Ni on the catalyst surface, and Ce1-xZrxO2-δ solid solution. The role of Ce1-xZrxO2-δ solid solution in Ni/CeO2–ZrO2 catalyst was observed as bi-functional; acceleration of water-gas-shift and oxidation of carbon reaction. The high resistance of Ni/CeO2–ZrO2 towards the coke formation showed its potential to establish a cost-effective commercial-scale biomass steam gasification process. This study is expected to provide a promising solution for the disposal of furniture wastes for production of clean energy (biohydrogen).

Steam-gasification of linear low-density polyethylene (LLDPE) waste to hydrogen-rich gas has been studied systematically over nickel (10 wt.%) loaded on a variety of supports (Al2O3, CeO2, and CeO2-ZrO2) synthesized using a novel solvent deficient method (SDM). The hydrogen selectivity order of the catalysts was reported as Ni/CeO2-ZrO2>Ni/CeO2>Ni/Al2O3. The highest catalytic H2 selectivity of the Ni/CeO2-ZrO2 catalyst was reported to be ∼76 vol.%, and was attributed to the smaller nickel crystals that were finely dispersed on the support, and to formation of Ce1-xZrxO2-δ solid solutions. The Ce1-xZrxO2-δ solid solution in the Ni/CeO2-ZrO2 catalyst was observed to be bi-functional, thus reflecting the acceleration of the water gas shift and the oxidation of carbon to CO and CO2. The better resistance of the Ni/CeO2-ZrO2 catalyst towards coke deposition also indicated its potential for commercial-scale applications for the steam gasification of plastics. Therefore, this research provides an advanced route to recycle LLDPE plastic waste into hydrogen fuel, which presents both economical and environmental benefits.

Polycyclic aromatic hydrocarbons (PAHs) are known as a hazardous group of pollutants in the soil which causes many challenges to the environment. In this study, the potential of biochar (BC), as a carbonaceous material, is evaluated for the immobilization of PAHs in soils. For this purpose, various bonding mechanisms of BC and PAHs, and the strength of bonds are firstly described. Also, the effect of impressive criteria including BC physicochemical properties (such as surface area, porosity, particle size, polarity, aromaticity, functional group, etc., which are mostly the function of pyrolysis temperature), number of rings in PAHs, incubation time, and soil properties, on the extent and rate of PAHs immobilization by BC are explained. Then, the utilization of BC in collaboration with biological tools which simplifies further dissipation of PAHs in the soil is described considering detailed interactions among BC, microbes, and plants in the soil matrix. The co-effect of BC and biological remediation has been authenticated by previous studies. Moreover, recent technologies and challenges related to the application of BC in soil remediation are explained. The implementation of a combined BC-biological remediation method would provide excellent prospects for PAHs-contaminated soils.

Green and sustainable hydrogen from biomass gasification processes is one of the promising ways to alternate fossil fuels-based hydrogen production. First off, an overview of green hydrogen generation from biomass gasification processes is presented and the corresponding possible gasification reactions and the effect of respective experimental criteria are explained in detail. In addition, a comprehensive explanation of the catalytic effect on tar reduction and hydrogen generation via catalytic gasification is presented regarding the functional mechanisms of various types of catalysts. Furthermore, the commercialization aspects, the associated technical challenges and barriers, and the prospects of a biomass gasification process for green hydrogen generation are discussed. Finally, this comprehensive review provides the related advancements, challenges, and great insight of biomass gasification for the green hydrogen generation to realize a sustainable hydrogen society via biomass valorization.

This research studied the catalytic pyrolysis of oil sludge (OS) over metal-loaded HZSM-5 catalysts, an eco-friendly and cost-effective technology to produce value-added aromatics such as benzene, toluene, ethylbenzene, and xylene (BTEXs). In particular, it evaluated the respective effects of the experimental parameters: the type and amount of the metal loaded, the reaction temperature, and the OS/catalyst ratio, on the BTEXs yield sequentially to achieve optimum conditions. This evaluation showed that the highest yields of the BTEXs (6.61 wt%) and other aromatics were achieved when Ni was incorporated into the HZSM-5 (Ni/HZSM-5) followed by the corresponding yields of Ga/HZSM-5 and Fe/HZSM-5, due to a better distribution of Ni on the support surface and an enhanced acidity strength of this catalyst. Further, increase in Ni loading (up to 10 wt% Ni/HZSM-5) increased the BTEXs yield to 13.48 wt%. However, the excessive Ni loading (15 wt% Ni/HZSM-5) resulted in a reduced BTEXs yield due to the blockage of the zeolite channels. Next, an increase in the reaction temperature from 500 °C to 600 °C increased the yield of the BTEXs and other aromatics. However, a further increase in the reaction temperature to 650 °C decreased slightly their yield because of the stimulating secondary reactions at high temperatures. The increase of catalyst amount (OS/catalyst of 1/3) also maximized the BTEXs yield (30.50 wt%).

Polychlorinated biphenyls (PCBs) are hazardous organic contaminants threatening human health and environmental safety due to their toxicity and carcinogenicity. Biochar (BC) is an eco-friendly carbonaceous material that can extensively be utilized for the remediation of PCBs-contaminated soils. In the last decade, many studies reported that BC is beneficial for soil quality enhancement and agricultural productivity based on its physicochemical characteristics. In this review, the potential of BC application in PCBs-contaminated soils is elaborated as biological strategies (e.g., bioremediation and phytoremediation) and specific mechanisms are also comprehensively demonstrated. Further, the synergy effects of BC application on PCBs-contaminated soils are discussed, in view of eco-friendly, beneficial, and productive aspects.

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO

This is the first study on air gasification of furniture waste (FW) over Ni-loaded ultra-stable Y-type zeolites (Ni-USY) to produce biohydrogen. Effects of SiO2/Al2O3 ratio of USY (5, 30, and 60), Ni loading (5, 10, 20, and 30 wt.%) onto the support, and reaction temperature (700, 750, and 800 °C) on catalytic air gasification were investigated. The Ni-USY(5) led to a relatively higher gas yield (72.19 wt.%) and higher volume percent of H2 (31.94 vol.%) and CO (34.57 vol.%) and lower CH4 and C2-C4 yields than the Ni-USY(30) and Ni-USY(60). An increase in the Ni loading onto USY(5) support from 5 wt.% to 30 wt.% did not affect the yield of gas. The concentrations of H2 (41.16 vol.%) and CO (38.62 vol.%) increased as increasing Ni loading from 5 wt.% to 20 wt.%. The H2 and CO concentrations significantly decreased as the Ni loading became over 20 wt.%. Increasing the temperature from 700 to 800 °C increased the yields of H2 and CO and decreased the yields of CO2, CH4, and C2-C4. The contents of harmful compounds (e.g., benzene derivatives, phenolics, and polycyclic aromatic hydrocarbons) in liquid product were suppressed when using the Ni-USY(5). The air gasification with the Ni-USY catalysts could offer as an emerging technology to transform FW to H2-rich syngas with low contents of harmful pollutants.

Steam and air gasification with 5 wt% Ni/Al

The purpose of this study is to synthesize activated carbon (AC) from the Iranian pine cone tree (Pinus eldarica) for the removal of sodium dodecylbenzene sulfonate (SDBS) from aqueous solution in batch experiments. Phosphoric acid with different saturation ratios is used for the synthesis of AC. The pyrolysis process is carried out in a ceramic furnace under nitrogen gas flow equal to 100 ml min−1 with a heating rate of 8 °C min−1 to 3 h in 750 °C. The precursor and synthesized ACs are characterized by titration, proximate, ultimate, elemental analysis, Boehm titration, SEM, BET, FT-IR, TGA, and XRF analysis. The acidic functional group is the most dominant group on the surface of prepared AC. The maximum surface area of 1580 m2 g−1 was obtained at an impregnation of 2 gg−1. The synthesized AC with a different impregnation ratio is used to remove the SDBS from aqueous solution in the batch system. The results show that AC with an impregnation ratio of 4 has the highest absorption capacity (93.10 mgg−1). The experimental kinetic data are analyzed with pseudo-first-order, pseudo-second-order, and intraparticle diffusion models. The results showed that pseudo-second-order kinetic model provides a better description of the adsorption process with R2 > 0.952.

This study highlights the potential of pyrolysis of food waste (FW) with Ni-based catalysts under CO2 atmosphere as an environmentally benign disposal technique. FW was pyrolyzed with homo-type Ni/Al2O3 (Ni–HO) or eggshell-type Ni/Al2O3 (Ni-EG) catalysts under flowing CO2 (50 mL/min) at temperatures from 500 to 700 °C for 1 h. A higher gas yield (42.05 wt%) and a lower condensable yield (36.28 wt%) were achieved for catalytic pyrolysis with Ni-EG than with Ni–HO (34.94 wt% and 40.06 wt%, respectively). In particular, the maximum volumetric content of H2 (21.48%) and CO (28.43%) and the lowest content of C2–C4 (19.22%) were obtained using the Ni-EG. The formation of cyclic species (e.g., benzene derivatives) in bio-oil was also effectively suppressed (24.87%) when the Ni-EG catalyst and CO2 medium were concurrently utilized for the FW pyrolysis. Accordingly, the simultaneous use of the Ni-EG catalyst and CO2 contributed to altering the carbon distribution of the pyrolytic products from condensable species to value-added gaseous products by facilitating ring-opening reactions and free radical mechanisms. This study should suggest that CO2-assisted catalytic pyrolysis over the Ni-EG catalyst would be an eco-friendly and sustainable strategy for disposal of FW which also provides a clean and high-quality source of energy.

This manuscript evaluates the behavior of activated carbon (AC) prepared from the cones biomass of Iranian pine trees, with high mesoporosity and a large specific surface area, as a high potential adsorbent for sodium dodecylbenzene sulfonate (SDBS) in batch and continuous systems. The AC samples were prepared from pine tree cones by chemical activation with different impregnation ratios of K 2 CO 3 and KOH. The materials were characterized by Boehm titration, approximate elemental, SEM, FT-IR, TGA, XRF analyses and BET surface area measurement. In a batch process, the effects of various parameters such as adsorbent dose, pH, contact time and initial SDBS concentration and temperature were considered. Six different adsorption isotherms were applied to equilibrium data. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were used to estimate the adsorption kinetic data. The experimental data resulted in excellent fits with the Redlich-Peterson isotherm and that the pseudo-second-order described the best description of adsorption data. Thomas and Yan models were used in describing the experimental data in a continuous system. The thermodynamic parameters such as Gibbs free energy (ΔG°), enthalpy (ΔH°), entropy (ΔS°) and activation energy (E a ) were analyzed. The contrasting negative and positive values of ΔG° and ΔH°, respectively, indicated that adsorption was spontaneous and endothermic in nature, and the obtained E a confirmed chemisorption of SDBS adsorption onto AC. The adsorptive behavior of AC was also investigated with different bed heights, flow rates and the initial concentrations of SDBS. These results, by the recovery of 88% after five successive cycles, indicated that the combination of sulfuric acid and ethanol with a ratio of 4:6 is suitable for desorbing SDBS from AC.

Steam and air gasification with 5 wt% Ni/Al2O3 eggshell (Ni-EG) and homo (Ni-H) catalysts were performed for the first time to produce biohydrogen from food waste. The steam gasification produced comparably higher gas yield than air gasification. In non-catalytic experiments, steam gasification generated a higher volume percent of H2, whereas more CO, CO2, CH4, and C2-C4 were produced in air gasification. Ni-EG demonstrated higher potential to obtain H2-rich gases with a low C2-C4 content compared to that obtained by Ni-H, particularly in steam gasification at 800 °C, which produced gaseous products with 59.48 vol% H2. The long-term activity of both catalysts in steam gasification was evaluated, and Ni-EG exhibited higher stability than Ni-H. The ideal distribution of Ni species on the outer region of γ-Al2O3 pellets in Ni-EG resulted in higher activity, stability, and selectivity than Ni-H in both steam and air gasification.