Removal of Aquatic Cadmium Ions Using Thiourea Modified Poplar Biochar

Abstract

Removal of aquatic cadmium ions using biochar is a low-cost method, but the results are usually not satisfactory. Modified biochar, which can be a low-cost and efficient material, is urgently required for Cd-polluted water and soil remediation. Herein, poplar bark (SB) and poplar sawdust (MB) were used as raw materials to prepare modified biochar, which is rich in N- and S- containing groups, i.e., TSBC-600 and TMBC-600, using a co-pyrolysis method with thiourea. The adsorption characteristics of Cd2+ in simulated wastewater were explored. The results indicated that the modification optimized the surface structure of biochar, Cd2+ adsorption process by both TSBC-600 and TMBC-600 was mainly influenced by the initial pH, biochar dosage, and contact time, sthe TSBC-600 showed a higher adsorption capacity compared to TMBC-600 under different conditions. The Langmuir adsorption isotherm model and pseudo-second-order kinetic model were more consistent with the adsorption behavior of TSBC-600 and TMBC-600 to Cd2+, the maximum adsorption capacity of TSBC-600 and TMBC-600 calculated by the Langmuir adsorption isotherm model was 19.998 mg/g and 9.631 mg/g, respectively. The modification method for introducing N and S into biochar by the co-pyrolysis of biomass and thiourea enhanced the removal rate of aquatic cadmium ions by biochar.

Remediation of Soil Polluted with Cd in a Postmining Area Using Thiourea-Modified Biochar

“…The resulting material was labeled as PBC600. In addition, the modified biochar (TPBC600) was prepared as reported by Zhu et al [ 30 ]. Briefly, a mixture with a mass ratio of 1:1 of poplar bark and thiourea was thoroughly mixed and placed in a tubular furnace.…”

“…Procedures used for the physical and chemical characterization of PBC600 and TPBC600 were as reported by Zhu et al [ 30 ]. Total Cd content was determined using inductively coupled plasma mass spectrometry (ICP-MS) after soil digestion with HNO 3 -HF [ 35 ].…”

“…As a cheap and widely used surface modifier, thiourea could increase the bonding of amine and mercaptan functional groups and improve the adsorption capacity of heavy metals. In our previous work, we investigated the removal efficiency of Cd in aqueous solutions by using thiourea-modified biochar (TPBC600) [ 30 ]. However, cadmium adsorption in aqueous solutions was significantly different from that in soil colloids.…”

Dithiocarbamate modification of activated carbon for the efficient removal of Pb(ii), Cd(ii), and Cu(ii) from wastewater

“…39 Additionally, the survey spectrum for the composite confirmed the existence of all precursor elements from the DTC-AC. 40 And XPS survey spectra of DTC-AC and Cu-loaded DTC-AC are shown in Fig. S1 (ESI†).…”

A review of prospects and current scenarios of biomass co-pyrolysis for water treatment

“…The second study, using halloysite and coconut shell co-pyrolyzed char, showed optimal lead adsorption at pH 5 [90]. Furthermore, a further study revealed good adsorption results for cadmium at a higher pH using a thiourea modified poplar biochar [91]. Acidic and neutral pH levels were preferred for phenol removal by coal tar pitch and vinasse co-pyrolyzed char, owing to the lower dissociation of phenol at the specified conditions and hence, easier removal.…”