Municipal solid waste incineration (MSWI) fly ash (FA) is classified as hazardous waste, which requires additional treatment before disposal or further utilization. Stabilization/solidification (S/S) is regarded as a low-cost and high-efficient method for MSWI FA treatment. “Low-carbon S/S” has captured extensive interest in recent years, which could treat hazardous wastes and enable resource recycling in a sustainable way. This article introduced the state-of-art low-carbon S/S strategies for MSWI FA treatment. The immobilization mechanisms of pollutants in various matrices were also discussed. Prospects were raised to foster the actualization of sustainable management of MSWI FA.

Gasification of biomass produces a syngas containing trace amounts of viscous hydrocarbon tar, which causes serious problems in downstream pipelines, valves and processing equipment. This study focuses on the use of tire-derived pyrolysis char for tar conversion using biomass tar model compounds representative of tar. The catalytic decomposition of tar model compounds, including methylnaphthalene, furfural, phenol, and toluene, over tire char was investigated using a fixed bed reactor at a bed temperature of 700 °C and 60 min time on stream. The influence of temperature, reaction time, porous texture, and acidity of the tire char was investigated with the use of methylnaphthalene as the tar model compound. Oxygenated tar model compounds were found to have higher conversion than those containing a single or multi-aromatic ring. The reactivity of tar compounds followed the order of furfural?>?phenol?>?toluene?>?methylnaphthalene. The conversion of the model compounds in the presence of the tire char was much higher than tar thermal cracking. Gas production increased dramatically with the introduction of tire char. The H2 potential for the studied tar model compounds was found to be in the range of 40%–50%. The activity of tire char for naphthalene removal was compared with two commercial activated carbons possessing a very well-developed porous texture. The results suggest that the influence of Brunauer-Emmett-Teller surface area of the carbon on tar cracking is negligible compared with the mineral content in the carbon samples.

The vastly increasing generation of plastic packaging waste has outgrown the infrastructure capacity to manage this waste effectively, resulting in critical aquatic and terrestrial pollution. In 1994, the European Commission implemented the Packaging and Packaging Waste Directive 94/62/EC, responding to growing concerns regarding the environmental impact of packaging and safe waste management. This study analyses how Germany, Spain, France, Italy, and Poland—the five most populous countries in the EU (European Union)—manage their plastic packaging waste, and evaluates their established Extended Producer Responsibility (EPR) schemes, which are mandatory for all EU Member States by the end of 2024. This research shows that EPR schemes improve the financial and operational viability of plastic waste management in the scope countries, resulting in higher collection and recycling rates. Take-back requirements can incentivise producers to put less plastic packaging on the market, and advanced disposal fees can encourage eco-design. The Producer Responsibility Organisation plays a crucial role in both producer and consumer awareness, and in ensuring that plastic waste is safely managed. However, the local recycling infrastructure of 6.5 Mt in 2018 is a major barrier to reaching 50% recycling of plastic packaging in the EU by 2025. The European recycling capacity only covered about 23% of the cumulative post-consumer plastic waste generation, delaying the transition to the EU circular plastic economy. The recycling capacity has increased by 3 Mt between 2018 and 2020 and needs to continue its rapid expansion to become autonomous in reaching the recycling targets.

In this study, Mn-based bimetallic oxide catalysts were synthesized via the solvothermal method. Different metals (Ce, Co and Fe) exhibited a great impact on the physicochemical properties of catalysts, resulting in different catalytic activities for the simultaneous removal of 1,2-dichlorobenzene (1,2-DCB) and furan, as a model of polychlorinated dibenzodioxins and dibenzo-furans (PCDD/Fs). Fe–MnOx presented the best catalytic activity, with a removal efficiency of 62% for 1,2-DCB and 100% for furan at 240 °C. Several analytical techniques were employed, namely, Brunauer–Emmett–Teller (BET), X-ray diffraction (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR), and ammonia temperature programmed desorption (NH3-TPD). Compared with pure MnOx catalysts, Fe–MnOx shows a higher specific surface area of 117.9 m2/g. SEM observations showed flower-like nanosheet structures for Fe–MnOx. XPS analysis indicated that Mn4+/Mn3+ and active oxygen play the key roles in the catalytic oxidation of 1,2-DCB and furan. The catalytic activity, selectivity and stability of Mn-based bimetallic oxide catalysts for the oxidation of 1,2-DCB and furan were tested. Competition exists between 1,2-DCB and furan such that the adsorption of furan occurs prior to 1,2-DCB.

In this study, the method of fluidized incineration and water washing to recover hydrogen fluoride (HF) was proposed to dispose of high fluorine-containing organic waste. The resource utilization of the waste was investigated in a fluidized bed incinerator with a disposal capability of 10 t/d. The evolution characteristics of fluorine, operation conditions of the incineration system, absorption coefficient for HF by water washing, and HF corrosion during combustion were assessed. The results showed that HF and fluorocarbons were detected as the initial gaseous fluorides released during combustion. The release of HF could be divided into three stages, in which HF was generated from the volatilization of HF in the waste and the hydrolysis of fluorine in water-soluble salts (60–220 °C), oxidative decomposition of fluorinated organic components and residual carbon (220–800 °C), and hydrolysis of insoluble fluorinated inorganic minerals (800–1000 °C). Fluorocarbons could be destroyed through reactions with free radicals H, O, and OH or through single-molecule decomposition. Enhancing the temperature in the furnace and increasing the content of oxygen and hydrogen in the incineration materials were conducive to reducing the generation of fluorocarbons. By sampling and analyzing the bottom slag, bag filter ash and exhaust gas during the field test, the relevant pollutant discharge could meet the national emission standards. The waste heat utilization of high-temperature flue gas and the recovery of hydrofluoric acid and hydrochloric acid were realized. In the recovery of HF by water washing, the total absorption coefficients for 1# to 4# packed absorbers were 52.38 kg/(h m2), 39.96 kg/(h m2), 5.98 kg/(h m2) and 3.89 kg/(h m2), respectively. In the actual operation, alumina showed good corrosion resistance to high-temperature HF and could be used as bed materials or refractory materials. Low-temperature corrosion of HF occurred in the quenching heat exchanger, which was damaged after 6 months of continuous operation. High-temperature corrosion of HF occurred in the waste heat boiler. No significant corrosion was observed in the 24 months of operation.

Municipal solid waste (MSW) is a carbon–neutral energy source and possesses a moderate heating value; hence, it can be used as an alternative fuel for coal. To use high ash and high sulfur Indian coals efficiently, a techno economic analysis is performed for electricity generation using supercritical and subcritical based steam turbines operating in the oxy-fuel co-combustion mode of MSW with Indian coals. The impact of the capture of direct and indirect greenhouse gasses such as CO2, NOx and SOx on the net thermal efficiency of the power plants is assessed. The supercritical based steam turbine achieved a higher net thermal efficiency by 8.8% using MSW based feedstock compared to sub-critical conditions. The co-combustion mode reduced the levelized cost of electricity (LCOE) by 48–73 $/MWh. Techno-economic analysis for sulfur removal in coal using ultrasonication technology has not yet been reported in the literature. The incorporation of an ultrasonicator (a pre-combustion sulfur remover) and a duct sorbent injector (a post-combustion SOx absorber) increased the LCOE by 1.39–2.75 $/MWh. In high sulfur coals, the SOx emissions decreased from 224.79 mg/m3 to 9.2 mg/m3.

Ammonia (NH3) synthesis via electrocatalytic nitrogen reduction generally suffers from low NH3 yield and faradaic efficiency. Compared with activating stable, low-solubility N2, the electrochemical conversion of nitrates to ammonia provides a more reasonable route for NH3 production. Herein, we introduce Ar-plasma to enhance the interaction between copper-nickel alloys and carbon substrate to improve the performance of NH3 production. The NH3 faradaic efficiency from nitrate is nearly 100% and the yield rate is over 6000 μgNH3cm?2h?1. DFT (density functional theory) calculation reveals the high performance of Cu50Ni50 originates from the lower energy barrier on the reaction path and the closer position to the Fermi level of the d-band center. This work offers a promising strategy for plasma-modified electrocatalyst to promote ammonia synthesis via nitrate reduction.