Ammonium removal from groundwater using peanut shell based modified biochar: Mechanism analysis and column experiments

The remediation effects of peanut shell biochar (HBC) and Mg-modified peanut shell biochar (MHBC) prepared under pyrolysis temperatures of 300 °C and 600 °C on Cd2+ polluted brown soil were investigated in a pot experiment. The results showed that the biochar treatment increased soil pH and decreased the bioavailable Cd2+ content in the soil. Compared with the control treatment (CK), the pH value increased by 0.32 to 2.5 upon treatment with 1% and 2% of HBC and MHBC. Bioavailable Cd2+ in the soil decreased by 5.64% to 21.33% with HBC. The MHBC presented better amendment effects than HBC; bioavailable Cd2+ in the soil decreased by 26.2% to 50.1% with the addition of MHBC. The addition of HBC and MHBC increased the shoot height and decreased the root length of the spinach. Moreover, they significantly decreased the accumulation of Cd2+ in the shoots and roots of the spinach. Compared to CK, the Cd2+ content in the shoots decreased by 7.0% to 46.8% upon treatment with 1% and 2% of HBC and MHBC, while the Cd2+ content in the roots decreased by 7.3% to 52.7%. The Cd2+ content in the shoots and roots was more greatly decreased with MHBC than with HBC.

Download Full-text

Ammonium removal efficiency of biochar-based heterotrophic nitrifying bacteria immobilization body in water solution

Environmental Engineering Research ◽

10.4491/eer.2019.451 ◽

2020 ◽

Vol 26 (1) ◽

Author(s):

Chaoxu Wang ◽

Jing Ren ◽

Xin Qiao ◽

Mudassir Habib

Keyword(s):

Water Solution ◽

Nitrifying Bacteria ◽

Microbial Immobilization ◽

Adsorption Ability ◽

Ammonium Removal ◽

Removal Ratio ◽

Modified Biochar ◽

N Removal ◽

Biological Identification ◽

Heterotrophic Nitrifying Bacteria

In order to explore the performance of biochar-based microbial immobilization body in ammonium removal from water and potential mechanisms, a strain of heterotrophic nitrifying bacteria (HNB) was isolated from activated sludge, and the biochemical and molecular biological identification of HNB was carried out. Moreover, HNO3-, Mg2+-, NaOH-, and NaOH+Mg2+-modified rice husk-derived biochars were prepared. Then all the five kinds of biochars, including the original biochar, were used as carriers of HNB to remove NH4+-N from water. Results showed that HNB was classified as Pseudomonas, and the 72-h NH4+-N removal ratio of the free bacteria reached 80.24%. Compared with biochar itself, biochar-based HNB immobilization body showed a much stronger ability to remove NH4+-N, especially for NaOH- and NaOH+Mg2+-modified biochars. At the initial NH4+-N concentration of 100 mg/L and biochar addition dose of 10 g/L, NH4+-N removal ratio of NaOH- and NaOH+Mg2+-modified biochar-based HNB immobilization bodies reached 57.78% and 58.35% after 5 h, and reached 88.66% and 90.93% after 48 h respectively, which were obviously higher than the original, HNO3- and Mg2+-modified biochar-based HNB immobilization bodies. The phenomenon resulted from significantly higher bacteria adsorption ability of NaOH- and NaOH+Mg2+-modified biochars, which reached 773.75 and 941.17 nmol P/g biochar, respectively.

Download Full-text

Performance and Mechanism for Fluoride Removal in Groundwater with Calcium Modified Biochar from Peanut Shell

Science of Advanced Materials ◽

10.1166/sam.2020.3620 ◽

2020 ◽

Vol 12 (4) ◽

pp. 492-501 ◽

Cited By ~ 2

Author(s):

Rui-Ling Zhang ◽

Jing Xu ◽

Lei Gao ◽

Zhe Wang ◽

Bo Wang ◽

...

Keyword(s):

Calcium Chloride ◽

Functional Groups ◽

Removal Efficiency ◽

Low Cost ◽

Calcium Content ◽

Fluoride Removal ◽

Peanut Shell ◽

Modified Biochar ◽

Pseudo Second Order ◽

Safe Technique

Fluoride in groundwater poses a great risk to humans. Biochar is an effective and environmental-friendly adsorbent for fluoride removal. The objectives of this study were to develop a calcium modified biochar derived from peanut shell and to study its mechanism in the adsorptive removal of fluoride. For these purposes, biochar was prepared using three different techniques. No. 1 biochar was prepared by direct carbonization, No. 2 biochar was modifiied with 30% calcium chloride solution before carbonization, and No. 3 biochar was modified with 30% calcium chloride following carbonization. The No. 2 biochar clearly showed the highest percentage fluoride removal (92.1%) and the fluoride removal efficiency improved by 30%–60% compared with other techniques. The adsorption isotherms and kinetics of the biochar modified with calcium were best described by the Langmuir and pseudo-second-order model, respectively. Based on the calcium content from the energy spectrum, calcium was well loaded onto the biochar. Calcium detached experiments indicated the loaded calcium was the main method for fluoride removal of No. 2 biochar, the adsorption mechanism was clearly demonstrated through the changes of morphology and group during adsorption. Fourier transform infrared spectroscopic (FTIR) analyses indicated the highest fluoride removal efficiency of No. 2 biochar was due to cleavage and structural change in many functional groups. But only C–H was involved in No. 3 biochar fluoride removal process. The good performance of No. 2 biochar for de-fluoridation was due to the calcium stably loaded onto the biochar and many of the changed functional groups there. Biochar modified with calcium before carbonization is an efficient, low-cost, safe technique for de-fluoridation.

Download Full-text