Application of a breakthrough biosorbent for removing heavy metals from synthetic and real wastewaters in a lab-scale continuous fixed-bed column

TLDR: Desorption studies indicated that metal-loaded biosorbent could be used after three consecutive sorption, desorption and regeneration cycles by applying a semi-simulated real wastewater.

About: This article is published in Bioresource Technology.The article was published on 2017-04-01 and is currently open access. It has received 198 citations till now. The article focuses on the topics: Biosorption.

Figures

Figure 4 Breakthrough curves of Cd, Cu, Pb and Zn adsorption onto modified MMBB from synthetic and semi-simulated municipal wastewater (bed heights = 21 cm, influent flow rate = 10 mL/min or HLR =1.578 m3/m2.h, influent each metal concentration = 20 mg/L, particle size = 425-600 m, room temperature = 23oC)

Figure 5 Desorption kinetic of Cd, Cu, Pb and Zn adsorbed on modified MMBB (10 g , desorption solution = 0.1 M HCl, flow rate = 10 mL/min or HLR = 1.578 m3/m2.h)

Figure 3 Effect of influent metal concentration on the breakthrough curve of Cd, Cu, Pb and Zn adsorption onto modified MBB (pH 5.5±0.1, bed heights = 21 cm, influent flow rate = 10 L/min or HLR = 1.578 m3/m2.h, particle size = 425-600 m, room temperature = 23oC)

Figure 2 Effect of bed height (MMBB weight= 5, 10 and 15 gr) on the breakthrough curve of Cd, Cu, Pb and Zn adsorption onto modified MMBB (pH 5.5±0.1, influent flow rate = 10 mL/min or HLR = 1.578 m3/m2.h , influent metal concentration = 20 mg/L, particle size = 425- 600 m, room temperature = 23oC )

Table 4 Desorption parameters for three cycles of biosorption and desorption cycles with semisimulated municipal wastewater

Table 2 Dynamic adsorption capacity of cadmium, copper, lead and zinc onto different adsorbents

Frequently asked questions

Q1. What are the contributions in "Application of a breakthrough biosorbent for removing heavy metalsfrom synthetic and real wastewaters in a lab−scale continuous fixed−bed column" ?

A continuous fixed−bed study was carried out utilising a breakthrough biosorbent, specifically multi−metal binding biosorbent ( MMBB ) for removing cadmium, copper, lead and zinc. The effect of operating conditions, i. e. influent flow rate, metal concentration and bed depth was investigated at pH 5. 5±0. 1 for a synthetic wastewater sample. 

Q2. What is the effect of bed depth on the breakthrough curves?

an increase in the bed depth resulted in a wide mass transfer zone, which made the breakthrough curves moderately steeper. 

Q3. What is the effect of the higher influent metal concentration on the breakthrough curves?

The higher influent metal concentration resulted in the faster breakthrough and saturation and as a consequence the sharper breakthrough curves shifted to the left. 

Q4. What is the effect of adsorption on the municipal wastewater?

As a result of successful metal removal by modified MMBB column, the effect ofco−existing ions in the municipal wastewater on the continuous adsorption processcould be negligible. 

Q5. How many g of each biosorbent was soaked in the same room?

10 g of each biosorbent was soaked in 1 L of mentioned mixture thoroughly shaken (150 rpm) for 24 hr at room temperature of 23oC. 

Q6. What is the effect of the concentration of the metal on the breakthrough curves?

The breakthrough curves of Cd2+, Cu2+, Pb2+ and Zn2+ were obtained from variations in the metal concentrationin the column influent with time. 

Q7. Why did the adsorption capacity increase as the concentration rose?

This is because at a higher concentration, mass transfer is enhanced due to themass gradient’s higher driving force, and led to an improvement in the adsorption capacity. 

Q8. What is the eluent for desorption of heavy metals?

In batch studies, desorption of Cd, Cu, Pb and Zn ions was evaluated by applying different desorbing agents and the best eluent was hydrochloric acid 

Q9. What was the effect of the desorption efficiency on the MMBB?

The desorption efficiency amounts decreased when the number of cycles rose from 48.08, 47.61, 57.37 and 45.88% in the first cycle to 22.80, 23.69, 34.44 and 23.80% in the third cycle for Cd, Cu, Pb and Zn. Biosorption and desorption efficiency progressively decreased, as the biosorption and desorption cycles continued as reported by Bulgariu and Bulgariu (2016). 

Q10. How long did the modified MMBB column remove heavy metals from municipal wastewater?

The results presented in Figure4 indicate that the modified MMBB packed−bed columnremoved more than 90% of Cd(II), Cu(II), Pb(II) and Zn(II) ions from 3227, 2617, 1714 and 2019 mL municipal wastewater in 322, 261, 171 and 201 minutes, respectively. 

Q11. How much is the breakthrough curves shown in Figure 3?

The effect of initial concentration on the breakthrough curves is shown in Figure 3, using a bed depth of 21 cm at a flow rate of 10 mL/min (HLR of 1.578 m3/m2.h).