Fabrication of bimetallic Ag/Fe immobilized on modified biochar for removal of carbon tetrachloride

Dechlorination of Excess Trichloroethene by Bimetallic and Sulfidated Nanoscale Zero-Valent Iron

“…To date, a variety of approaches to enhance the reactivity of nZVI for pollutant degradation have been explored. ,− The most used approach involves addition of a secondary metal to form iron-based bimetallic nanoparticles especially Fe–Pd, ,− Fe–Ni, − Fe–Cu, , and Fe–Ag. , Researches showed that bimetallic nanoparticles especially Fe–Pd degraded organic halides more completely into halogen-free products with reaction rates several orders of magnitude higher than bare nZVI under anoxic and excess iron conditions. ,, The enhanced reactivity of bimetallic particles was generally attributed to (1) the deposition of transition or noble metals (e.g., Pd, Ni, Cu, and Ag) formed galvanic couple with nZVI, which accelerates the electron transfer from Fe(0) core to metal additive on nZVI surface, ,, and (2) the metal additive catalyzes hydrodechlorination reaction. , …”

Characterization of biochars derived from different materials and their effects on microbial dechlorination of pentachlorophenol in a consortium

“…[8][9][10] Due to its porous, large internal surface area and high aromaticity, biochar has also been reported to enhance the adsorption of various organic and metal pollutants and effectively immobilize these environmental pollutants, thereby reducing their bioavailability and ecotoxicity. [11][12][13][14][15] Many studies have investigated the application of biochar or modied biochar for the removal of organic and metal pollutants; however, most of these studies have focused on its adsorption capacity. For example, biochar obtained from cottonseed hulls exhibits a very high adsorption affinity for various pesticides, 13 cow manure biochar was utilized as a potential adsorbent to remove oxytetracycline and carbaryl from aqueous solutions, 12 and dairy-manure biochar can immobilize lead and atrazine in soil to reduce their toxicity.…”

“…11 In addition, modied biochar with nanoscale zero-valent iron and silver showed higher carbon tetrachloride removal efficiency than the original biochar as a novel adsorbent. 14 Recently, biochar has been reported as a solid-phase electron shuttle to support microbial redox transformations. [16][17][18][19] Studies have shown that plant biomass-derived biochar had high capacities to accept and donate electrons, 18 rice straw-derived biochar signicantly accelerated electron transfer from Geobacter sulfurreducens cells to halogenated compounds for enhancing dechlorination, 19 and poultry litter and wastewater biosolids-derived biochar could shuttle electrons to promote the reductive removal of nitro herbicides and explosives, 17 which were potentially due to graphene moieties, surface functional groups, or redox-active metals harbored in biochar.…”

Water Purification of Classical and Emerging Organic Pollutants: An Extensive Review

“…Different parameters were investigated to reach the optimum: starting from 10 mg/L of pollutant at 25 • C and by adding 5 g/L of adsorbent, a removal efficiency equal to 82.72%, 99.40% and 89.42% for DCM, TCM and CTC, respectively, was obtained. Carbon tetrachloride was also removed by Wu and Feng [48] using a modified biochar obtained after the immobilization of nanoscale zero-valent iron onto it, and then by attaching the elemental silver to the iron surface (Ag/Fe/MB). Starting from a concentration of pollutants equal to 20 mg/L and at pH 6 and 25 • C, 0.5 g/L of adsorbent was able to remove 93.9% of the compound after 60 min, till the complete adsorption within 90 min.…”