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In this study, a green synthesis route was developed to prepare Ca and Co oxides supported carbon aerogel from renewable alginate. The sodium alginate was adopted as a template and carbon source, and a hydrogel with a three-dimensional and core-shell structure was chelated by introducing calcium and cobalt bimetals. The synthesized Ca Co oxides supported carbon aerogel can completely remove Hg0 in the HCl-containing waste gasification gas at room temperature. The Hg0 adsorption capacity on the 4Ca-1Co/CA adsorbent is as high as 4.02 mg/g when the 5% breakthrough occurs. At a 20% breakthrough of HCl, the captured amount of HCl could reach 175.37 mg/g. We concluded that the introduction of calcium and cobalt on the adsorbent provides sufficient active sites for the removal of HCl in a large amount, at the same time, the excellent oxygen supply capacity of Co species in an oxygen-free atmosphere can form active chlorine sites, which is conductive to enhance the removal of Hg0. Additionally, the 4Ca-1Co/CA adsorbent has the characteristics of wide temperature window and wide application range of space velocity, which can meet the needs of various working conditions. [Display omitted] • A green synthesis route to prepare Ca and Co oxides supported carbon aerogel from renewable alginate is provided. • There is a synergistic effect on removing HCl and Hg0 at 4Ca-1Co/CA adsorbent. • The introduction of Ca and Co provides sufficient active sites for the highly efficient removal of HCl and Hg0. • A wide temperature window and high space velocity could be performed on 4Ca-1Co/CA adsorbent. [ABSTRACT FROM AUTHOR]

Co-pyrolysis of coal and seaweed can not only effectively decrease the carbon footprint but also improve the quality and output of coal pyrolysis products, however, the influence of seaweed on thermal releasing behaviors of mercury during co-pyrolysis process are still unclear. In this work, the chlorella and Guizhou bituminous coal were mixed and used to reveal the mercury release behavior during co-pyrolysis by the temperature programmed pyrolysis experiments, thermogravimetric and differential thermogravimetric analysis (TG-DTG) and thermogravimetry-mass spectrometry (TG-MS) methods, offering a sufficient explanation on the control technology of mercury pollutants in co-pyrolysis. The results exhibited that a large amount of reducing gases such as CO, H 2 and H 2 O were generated in chlorella at the temperature range of 100-500°C, which was favorable for the transformation from oxidized mercury to elemental mercury, thus remarkably increased the release of elemental mercury in the raw coal sample. The mixed chlorella also significantly lowered the decomposition temperature range (from 400-600 to 300-400°C) of pyrite-bound mercury and decreased the decomposition temperatures of the pyrite-bound mercury species. Additionally, in the co-pyrolysis about 91.82% of mercury was released into the gas phase below 400°C and was 13.77% higher than that of in individual pyrolysis of coal. [Display omitted] [ABSTRACT FROM AUTHOR]

• The rod-like MnO 2 catalyst modified by Co-Ce oxide were controllable synthesized. • The doping amount of Co influenced the enhancement of catalytic performance. • The prepared catalyst exhibited long-term stability and excellent SO 2 tolerance. • The addition of Co prevented the active sites from being poisoned by SO 2. The Co was firstly used as a dopant to improve the NO and Hg0 removal performance of CeO 2 loaded rod-like MnO 2 catalyst (Ce/MnO 2) and its SO 2 resistance. The results showed the doping process effectively improved the relative concentrations of chemisorbed oxygen as well as the contents of surface Ce4+ and Mn4+, enhanced the redox ability of catalyst, which was conducive to the simultaneous removal performance of NO and Hg0 in flue gas. The Co-Ce/MnO 2 catalyst (the mole ratio of Co/Ce = 1.0) had optimal catalytic performance among all prepared catalysts in 160–280 °C, its NO and Hg0 removal efficiencies achieved 99.9% and 91.9% at 200 °C and 10,000 h−1, respectively. In addition, the Co-Ce/MnO 2 performed stronger resistance to SO 2 in comparison with Ce/MnO 2 , its catalytic activities decreased slightly when SO 2 with a concentration of 500 ppm was added into the gas stream, and then recovered close to the initial value after eliminating of SO 2. We considered the excellent SO 2 tolerance performance of Co-Ce/MnO 2 catalyst is assigned to the fact that the Co-modification restrained the sulfation of CeO 2 and MnO 2 to CeSO 4 and MnSO 4 , alleviated the decreasing of chemisorbed oxygen, and hindered the chemisorption of SO 2 on the catalyst. This work provided a promising prospect of Co-modification on Ce/MnO 2 as SO 2 resistant catalysts for simultaneous removal of NO and Hg0 from flue gas. [ABSTRACT FROM AUTHOR]

• The Au/MCM-48 absorbent was controllable synthesized for Hg0 removal in natural gas. • Ultrafine Au nanoparticles were embedded in the three-dimensional channels of MCM-48. • The Au/MCM-48 absorbent exhibited excellent tolerance for H 2 O and H 2 S. • The Hg0 adsorption capacity of Au/MCM-48 is up to 7.23 mg∙g−1 at 5% breakthough. • The spent absorbent could be regenerated without distinct degradation over 5 cycles. The H 2 O and H 2 S in natural gas are frequently deemed to have inhibitory influences on Hg0 removal performance of most noble metal based Hg0 absorbents, it is extremely significant to develop an efficient and regenerable Hg0 removal absorbent with excellent H 2 S and H 2 O tolerance. In the work, the Au/MCM-48 absorbent was controllable synthesized using a facile yet robust method for Hg0 removal in H 2 S and H 2 O containing natural gas. The ultrafine Au nanoparticles with a diameter of 1.4 nm were embedded and uniformly dispersed in the three-dimensional channels of MCM-48. The absorbent of 1 wt% Au achieved a complete Hg0 capture performance at 60,000 h−1 and 30 °C by forming Au-Hg amalgam, and its Hg0 adsorption capacity achieved to 7.23 mg∙g−1 at 5% breakthrough. The spent sample could be easily regenerated by thermal treatment without distinct degradation over 5 cycles. The introduction of H 2 S and H 2 O in gas flow had an inappreciable impact on Hg0 removal performance over the Au/MCM-48 absorbent. The excellent Hg0 adsorption efficiency, outstanding capture capacity and good regeneration performance of the absorbent due to the nano-confinement of MCM-48 channels, which prevents Au nanoparticles from growing and agglomerating. Excellent H 2 O tolerance is attributed to the good hydrophobicity of MCM-48 modified by trimethylchlorosilane, and the high H 2 S tolerance is due to the fact that the Au nanoparticles lack reactivity toward H 2 S. This work provides a promising method for the preparation of effective and regenerable absorbents for demercuration in H 2 S and H 2 O containing natural gas. [ABSTRACT FROM AUTHOR]