Ice-phobic properties of MoS_(2)-loaded rice straw biogas residue biochar-based photothermal and anti-corrosion coating with low oxygen to carbon ratio

Icing of wind turbine blades will seriously hinder the development of the wind power industry,and the use of biomass resources to solve the icing problem is conducive to promoting the synergistic development of biomass and wind energy.In this study,ice-phobic coatings with photothermal and anti-corrosion properties were prepared by surface modification pyrolysis and hydrothermal reaction with rice straw biogas residue as raw material.The erosion of KOH and the surface modification of MoS_(2) produced a rough structure of the material,and the high-temperature pyrolysis and hydrothermal reaction promoted the dehydrogenation and decarboxylation reactions,which reduced the number of oxygen-containing functional groups and decreased the surface energy of the material.The ice-phobic coating has superhydrophobic properties with a contact angle of 158.32°.Due to the small surface area in contact with water,the coating was able to significantly reduce the icing adhesion strength to 53.23 kPa.The icing wind tunnel test results showed that the icing area and mass were reduced by 10.54%and 30.08%,respectively,when the wind speed was 10 m s^(−1) and the temperature was−10°C.Photothermal performance tests showed that the MoS_(2)-loaded material had light absorption properties,and the coating could rapidly warm up to 58.3℃under xenon lamp irradiation with photothermal cycle stability.The loading of MoS_(2) acts as a physical barrier,reducing the contact of corrosive media with the substrate,thus improving the anti-corrosion of the coating.This study has practical application value and significance for the development of the anti-icing field under complex environmental conditions.

Biogas residue biochar integrated with phosphate from its ash for the effective recovery of nutrients from piggery biogas slurry

Magnesium ammonium phosphate(MAP)precipitation generally requires an external phosphorus source to increase the recovery of NH_(4)^(+)-N from biogas slurry.However,P-rich piggery biogas residue has been ignored as a phosphorus source.In this study,biogas residue was carbonized into biogas residue biochar(BRC),followed by acid leaching to synthesize functionalized BRC and release PO_(4)^(3−)-P from its ash as the phosphorus source.The effects of different acids on the leaching efficiency and morphological changes of P in BRC were investigated,and NH_(4)^(+)-N and PO_(4)^(3−)-P in the biogas slurry were recovered with functionalized BRC and MAP precipitation.The results showed that oxalic acid-hydrochloric acid mixed acid could leach more than 96%of P in BRC,while weakening the inhibitory effect of Ca^(2+)on MAP precipitation.The BRC was mainly composed of inorganic P,and most nonapatite IP and apatite P(Ca_(3)(PO_(4))2)were leached during acid leaching,with the latter more easily leached.Under optimal recovery conditions,the method had a significant recovery effect on NH_(4)^(+)-N(96.4%)and PO_(4)^(3−)-P(99.3%)in biogas slurry.The recovery of NH_(4)^(+)-N and PO_(4)^(3−)-P by functionalized BRC was mainly through chemical precipitation(forming NH_(4)MgPO_(4)·H_(2)O precipitate)while bonding with-OH,C=O and C-H functional groups.The final recovery product was also a BRC-based slow-release N-P fertilizer rich in struvite.This study solved the disposal problems of P-rich biogas residue and N-rich biogas slurry while providing an innovative technology for the resource utilization of faecal sewage at pig farms.