Investigation of heavy metal (Cu, Pb, Cd, and Cr) stabilization in river sediment by nano-zero-valent iron/activated carbon composite

Abstract

Nano-zero-valent iron/activated carbon (nZVI/AC) composite was evaluated for its effectiveness in the stabilization of Cu, Pb, Cd, and Cr in dredged river sediment. Synthetic precipitation leaching procedure (SPLP) and toxicity characteristic leaching procedure (TCLP) were adopted to compare the effects of nZVI/AC dosage, particle size, time duration, and temperature on heavy metal leachability. The results show that leachability dropped considerably with the addition of nZVI/AC and powdered particles in the size of 0.075-0.18 mm was more effective in stabilization than granular ones. Stabilization effect was stable in long-term and robust against changes in temperature. Tessier sequential extraction revealed that heavy metals were associated with solid particle, inorganic or organic matters in sediment. The addition of nZVI/AC was able to convert relatively weakly bound heavy metals into more strongly bound species and thus reduce the bioavailability and toxicity. Also, the standard potential of heavy metals may decide the mechanism of stabilization process.

Nanoremediation of As and metals polluted soils by means of graphene oxide nanoparticles

“…This mechanism has already been observed in carbon nanotubes 21 . With regard to nZVI, the excellent results obtained in the immobilization of Pb are consistent with the findings of other studies 28,51,52 . This decrease in the available concentrations of Pb, and only slightly of Zn, negatively correlated with the increase in nZVI dose (−0.97, P < 0.01; −0.71, P < 0.05 respectively).…”

“…The reactivity of nGOx is conferred by a large specific surface area and the presence of a large amount of chemically bonded oxygen on the surface, including carbonyl and carboxyl groups at the layer ends and hydroxyl and epoxy groups on the base plane [24][25][26][27] . Thus, the functional groups containing oxygen atoms have lone electron pairs that can efficiently bind a metal ion to form a metal complex via electrostatic interaction and coordination 23,28 . Also, the presence of these oxygen atoms allows hydrogen to bind to water molecules, thereby conferring nGOx solubility in water 29 .…”

Teknik-Teknik Remediasi Sedimen Terkontaminasi Logam Berat

“…Sementara pengendapan dilakukan dengan mengubah logam berat terlarut menjadi fase padatannya seperti logam hidroksida, logam karbonat, logam fosfat dan logam sulfida (Tsezos, 2009). Sedangkan perubahan senyawa logam berat dapat mengubah sifat logam dari zat yang berbahaya menjadi zat yang tidak berbahaya (Chen et al, 2015). Pada tulisan ini akan dipaparkan metode remediasi sedimen yang terkontaminasi logam berat, yaitu metode fisika-kimia, metode biologi dan metode gabungan.…”

Cr (VI) Removal from Aqueous Solution Using Starch and Sodium Carboxymethyl Cellulose-Coated Fe and Fe /Ni Nanoparticles

“…The XRD patterns of SS-nZVI-Ni before reaction with Cr(VI) showed a peak of To further investigate the removal mechanism, the microstructural features of SS-nZVI-Ni before and after reaction with Cr(VI) were analyzed by SEM (Figs 3a and 3c, respectively), SS-nZVI-Ni existed in the form of a sphere, with sizes ranging from 100~150 nm. NZVI-Gr coated by starch [13], nZVI supported by pumice [22], and nZVI supported by activated carbon [23] gained similar results. While after reaction, the SEM images showed that SS-nZVI-Ni particles become larger, with sizes ranging from 200~250 nm.…”