Functionalized graphene nano-platelets(FGN) were obtained via treating graphene nanoplatelets(GN) with HNO3, and served as adsorbent for the removal of Pb2+from solutions. We investigated the FGN adsorption capacity f...Functionalized graphene nano-platelets(FGN) were obtained via treating graphene nanoplatelets(GN) with HNO3, and served as adsorbent for the removal of Pb2+from solutions. We investigated the FGN adsorption capacity for Pb2+at different initial concentrations, varying pH, contact time and temperature. The characterization results of scanning electron microscopy(SEM), thermal analysis(TG/DTG), Fourier transform infrared spectroscopy(FT-IR) and Brunauer-Emmett-Teller(BET) method indicated that FGN layers were thin and possess large specific area with oxygen-containing functional groups grafted onto their surface. Meanwhile, the determined equilibrium adsorption capacity of FGN for Pb2+was 57.765 mg/g and adsorption isotherms well confirmed to Langmuir isotherms models. The results reveals that the FGN has better effect of water treatment.展开更多
Mineral carbonation using waste cement is a promising method to solve the problems caused by CO_2 emission and waste cement. Compaction pressure is an important parameter for mineral carbonation of calcium hydroxide, ...Mineral carbonation using waste cement is a promising method to solve the problems caused by CO_2 emission and waste cement. Compaction pressure is an important parameter for mineral carbonation of calcium hydroxide, one of the most dominant composite of waste cement that can be carbonated. The carbonation degree, morphology of products and compressive strength of carbonated compacts are influenced by compaction pressure significantly. Results show that the carbonation degree of calcium hydroxide increases at first（0-8 MPa） and then decreases in the higher compaction pressure range（10-14 MPa）. At the meantime, results also indicate that lower compaction pressure accelerates the early carbonation but hinder carbonation in the later stages. For the morphologies of carbonation products, calcium carbonate tends to form typical crystal morphology of calcite（rhombohedral） under lower compaction pressure, while it will become ellipsoidlike when compaction pressure reaches 8 MPa. TGA and water content results show that there is an optimal water content for the carbonation. In addition, lower water content is adverse to the carbonation at later stage and the CO_2 is difficult to penetrate into the inside of compacts when water content is high, which will hinder the carbonation. XRD and TGA results show that the carbonation products are calcite and small amount of amorphous calcium carbonate.展开更多
基金Funded by the National Natural Science Fundation of China(Nos.51678111 and 51478082)
文摘Functionalized graphene nano-platelets(FGN) were obtained via treating graphene nanoplatelets(GN) with HNO3, and served as adsorbent for the removal of Pb2+from solutions. We investigated the FGN adsorption capacity for Pb2+at different initial concentrations, varying pH, contact time and temperature. The characterization results of scanning electron microscopy(SEM), thermal analysis(TG/DTG), Fourier transform infrared spectroscopy(FT-IR) and Brunauer-Emmett-Teller(BET) method indicated that FGN layers were thin and possess large specific area with oxygen-containing functional groups grafted onto their surface. Meanwhile, the determined equilibrium adsorption capacity of FGN for Pb2+was 57.765 mg/g and adsorption isotherms well confirmed to Langmuir isotherms models. The results reveals that the FGN has better effect of water treatment.
基金Funded by the National Natural Science Foundation of China(51172096)the Ministry of Education Program for New Century Excellent Talentsthe Fundamental Research Funds for the Central Universities
文摘Mineral carbonation using waste cement is a promising method to solve the problems caused by CO_2 emission and waste cement. Compaction pressure is an important parameter for mineral carbonation of calcium hydroxide, one of the most dominant composite of waste cement that can be carbonated. The carbonation degree, morphology of products and compressive strength of carbonated compacts are influenced by compaction pressure significantly. Results show that the carbonation degree of calcium hydroxide increases at first（0-8 MPa） and then decreases in the higher compaction pressure range（10-14 MPa）. At the meantime, results also indicate that lower compaction pressure accelerates the early carbonation but hinder carbonation in the later stages. For the morphologies of carbonation products, calcium carbonate tends to form typical crystal morphology of calcite（rhombohedral） under lower compaction pressure, while it will become ellipsoidlike when compaction pressure reaches 8 MPa. TGA and water content results show that there is an optimal water content for the carbonation. In addition, lower water content is adverse to the carbonation at later stage and the CO_2 is difficult to penetrate into the inside of compacts when water content is high, which will hinder the carbonation. XRD and TGA results show that the carbonation products are calcite and small amount of amorphous calcium carbonate.
