Thermodynamic, kinetic, and equilibrium studies of Cu(II), Cd(II), Ni(II), and Pb(II) ion biosorption onto treated Ageratum conyzoid biomass.

The issue of environmental contamination, particularly caused by the existence of heavy metal particles, is a major and widely recognized subject that receives substantial global attention. The remediation of Cu(II), Cd(II), Ni(II), and Pb(II) ionic metal particles from synthetic wastewater using chemically treated plant leaves of Ageratum conyzoides (TAC) as a biosorbent was investigated. The biosorption process was implemented utilizing a batch system, wherein several operational parameters were considered, including temperature, pH, agitation time, biosorbent dosage, and initial concentration of the metal ion. Langmuir, Freundlich, Temkin, and D-R isotherm models were used to evaluate equilibrium data. The analyzed parameter exhibits characteristics that were best fitted with the Langmuir isotherm. The observed biosorption capacities (qm) of Cu(II), Pb(II), Ni(II), and Cd(II) ions on the TAC were measured as 51.573, 30.49, 33.53, and 35.91 mg/g, respectively, at a temperature of 22 °C. The affinity sequence of these metal ions follows the order Cu(II) > Pb(II) > Ni(II) > Cd(II). The measured values for the biosorption free energy change (ΔG) of Cu(II), Pb(II), Cd(II), and Ni(II) metal ions ranged from -1.017 to -4.723, -1.368 to -3.612, -2.785 to -5.21, and -1.047 to -5.135 kJ/mol, respectively. The enthalpy (ΔH) for Cu(II), Pb(II), Cd(II), and Ni(II) were determined to be +19.33, +6.82, +14.83, and +38.07 kJ/mol, respectively. Similarly, the corresponding entropy changes (ΔS) for the same series of metal ions were recorded as +0.075, +0.064, +0.063, and +0.135 kJ/mol.K. The pseudo-second-order kinetic models yielded superior outcomes in comparison to the pseudo-first-order kinetic models. The findings of the experiment indicated that the TAC demonstrates favorable efficacy in extracting all four metal ions. Hence, the utilization of biomass derived from Ageratum conyzoides leaves has proven to be a viable and economically feasible approach for biosorption of all four metals.

Rhizospheric bacteria: the key to sustainable heavy metal detoxification strategies.

The increasing rate of industrialization, anthropogenic, and geological activities have expedited the release of heavy metals (HMs) at higher concentration in environment. HM contamination resulting due to its persistent nature, injudicious use poses a potential threat by causing metal toxicities in humans and animals as well as severe damage to aquatic organisms. Bioremediation is an emerging and reliable solution for mitigation of these contaminants using rhizospheric microorganisms in an environmentally safe manner. The strategies are based on exploiting microbial metabolism and various approaches developed by plant growth promoting bacteria (PGPB) to minimize the toxicity concentration of HM at optimum levels for the environmental clean-up. Rhizospheric bacteria are employed for significant growth of plants in soil contaminated with HM. Exploitation of bacteria possessing plant-beneficial traits as well as metal detoxifying property is an economical and promising approach for bioremediation of HM. Microbial cells exhibit different mechanisms of HM resistance such as active transport, extra cellular barrier, extracellular and intracellular sequestration, and reduction of HM. Tolerance of HM in microorganisms may be chromosomal or plasmid originated. Proteins such as MerT and MerA of mer operon and czcCBA, ArsR, ArsA, ArsD, ArsB, and ArsC genes are responsible for metal detoxification in bacterial cell. This review gives insights about the potential of rhizospheric bacteria in HM removal from various polluted areas. In addition, it also gives deep insights about different mechanism of action expressed by microorganisms for HM detoxification. The dual-purpose use of biological agent as plant growth enhancement and remediation of HM contaminated site is the most significant future prospect of this article.

Estimation of sorption-desorption characteristics of biosorbent of Lantana camara leaves for removal of Pb (II) ions from wastewater.

This study points out the method regarding the removal of Pb (II) ions from water by treatment with Lantana camara leaves' biosorbent (LCLB). The sorption process was investigated by varying different parameters pH, contact time, adsorbent dose, initial metal ion concentration, and temperature. For a 5.00 g sorbent dose and a 45 min of the contact period, a Pb (II) ion solution with an initial metal ion concentration of 10 mg/L resulted in 90.7% maximum elimination at an optimum pH 6 and temperature 298 ± 1.5 K with LCLB. The adsorption process was spontaneous and exothermic. The maximum monolayer adsorption was 3.5 mg/g for Pb (II) sorption using LCLB. Adsorption of Pb (II) ions using LCLB (R2 > 0.999) followed the pseudo-second-order kinetics. The spectroscopic characterization was done by fourier transform infrared (FT-IR) analysis, while scanning electron microscope (SEM) images were captured for the morphological characterization. Desorption experiments revealed that hydrochloric acid has a strong potential as an eluent for Pb (II) ion desorption. The findings proposed that LCLB can be used as an effectual and cost-effective biosorbent for the expulsion of Pb (II) ions.