Mesoporous zirconium pyrophosphate for the adsorption of fluoride from dilute aqueous solutions

Hydroisomerization of 1-octene utilizing hierarchical SAPO-11-supported Ni catalysts: effect of the alkyl chain length of the mesoporogen

“…Beck et al 35 prepared a series of mesoporous materials (M41S) with different unit cell dimensions by changing the alkyl chain length of the quaternary ammonium surfactant compounds; the chain lengths studied were from C 8 (octyl trimethyl ammonium bromide, OTAB) to C 16 (cetyl trimethyl ammonium bromide, CTAB) and they found that the structure and pore diameter of MCM-41 were closely related to the chain length of the surfactant. Chen et al 36 synthesized mesoporous zirconium pyrophosphate (ZPP) adsorbents using C 8 (octyl trimethyl ammonium bromide, OTAB) to C 18 (octadecyl trimethyl ammonium bromide, OcTAB) alkyltrimethylammonium bromide as a mesoporogen and the results showed that the carbon chain length of the quaternary ammonium salt significantly affects the specific surface area of the mesoporous ZPP adsorbent. C 18 -ZPP shows the largest specific surface area and fluoride adsorption density.…”

Pilot-Scale Field Demonstration of Environmental Nanotechnology for Groundwater Defluoridation

“…To solve the problems of self-aggregation, difficulty in handling, and potential risk to ecosystem and human health, the nanomaterials were usually confined in the large porous matrix, such as polymeric ion exchange resin or activated carbon. − For instance, nanocomposite HZO@D201 was prepared through in situ growth of nano-hydrated zirconium oxide (HZO) inside the strongly alkaline anion exchange resin D201. − Thanks to the synergistic effects between the embedded nano-HZO and the D201 host, HZO@D201 exhibited a superior defluoridation performance than AA- and HAP-based materials, and negligible dissolution of HZO could be observed at pH > 2. More importantly, the exhausted HZO@D201 could be fully refreshed for cyclic use after simple treatment with the NaOH–NaCl binary solution. , In addition to HZO@D201, lots of other nanocomposite adsorbents have also been developed for fluoride pollution control. , However, in spite of extensive laboratory studies, ,,,,,, the field demonstration of nanotechnology for groundwater defluoridation is very rare. Until now, the applicability of nanocomposite adsorbents in practical water defluoridation still remains unclear.…”

“…20,21 In the past few decades, the rapid development of nanotechnology has offered a new chance for process innovation in water treatment. 22−24 The nanoscale oxides of Zr(IV), 25 Ti(IV), 8 and La(III) 26 can form an inner-sphere complex with fluoride even under strongly competing conditions, thereby holding tremendous promise in groundwater purification. To solve the problems of self-aggregation, difficulty in handling, and potential risk to ecosystem and human health, the nanomaterials were usually confined in the large porous matrix, such as polymeric ion exchange resin or activated carbon.…”

“…31,34 In addition to HZO@D201, lots of other nanocomposite adsorbents have also been developed for fluoride pollution control. 26,36 However, in spite of extensive laboratory studies, 8,15,16,25,26,34,36 the field demonstration of nanotechnology for groundwater defluoridation is very rare. Until now, the applicability of nanocomposite adsorbents in practical water defluoridation still remains unclear.…”

“…In the past few decades, the rapid development of nanotechnology has offered a new chance for process innovation in water treatment. − The nanoscale oxides of Zr­(IV), Ti­(IV), and La­(III) can form an inner-sphere complex with fluoride even under strongly competing conditions, thereby holding tremendous promise in groundwater purification. To solve the problems of self-aggregation, difficulty in handling, and potential risk to ecosystem and human health, the nanomaterials were usually confined in the large porous matrix, such as polymeric ion exchange resin or activated carbon. − For instance, nanocomposite HZO@D201 was prepared through in situ growth of nano-hydrated zirconium oxide (HZO) inside the strongly alkaline anion exchange resin D201. − Thanks to the synergistic effects between the embedded nano-HZO and the D201 host, HZO@D201 exhibited a superior defluoridation performance than AA- and HAP-based materials, and negligible dissolution of HZO could be observed at pH > 2.…”