Evaluation of the absorbance capacity of elements in meat effluent, and their mathematical models by using shrimp chitosan cross-linked glutaraldehyde

Abstract

Effluent from abattoir industries containing metals ions is known to adversely affect the quality fresh water. Water pollution is a global concern and its effects are difficult to reverse. This study evaluates the efficiency of the use of the shrimp chitosan cross-linked with glutaraldehyde as an adsorbent for the removal of cations in poultry and red meat effluent. The effluent was collected from different abattoirs in the Free State Province in the month of September 2019. Analysis of the physiochemical parameters of both effluent water samples revealed average pH values of between 8.6 and 8.8, electric conductivity (EC) of between 321 and 188 mS/m, turbidity (NTU) values of between 410 and 520, chemical oxygen demand (COD) of between 38 and 259 mg/L and total dissolved solutes (TDS) values of between 1663 and 1813 mg/L. ICP-MS results of both effluent samples showed the presence of alkali (Na and K), alkaline earth metals (Mg, Ca, Sr and Ba) of less than 10 mg/L and transition elements (Cu, Ni, Fe, Cd, Mn and Zn) of ±5 mg/L. The shrimp chitosan cross-linked with glutaraldehyde was first tested on a certified reference material (CRM) to determine the traceability measurement. Results obtained from the CRM revealed an increased adsorption from Sr < K < Mn < Al < Mg < Fe < Na < Ni < Cu < Ca < Cd < Ba < Zn. Analysis of both eluents water from the red and poultry meat effluent samples shows between 55 and 70% of the alkali (Na and K) and alkaline earth metals (Ca and Mg) adsorbed. The obtained t-values (range −1.7 and 3.6) for each elemental analysis were acceptable at 95% confidence interval. Using experimental data new mathematical model were constructed for uptake of Mn, Fe and Zn from abattoir effluent via the adsorbent. For the % PA and % RM, the obtained date show fading memory process with a delay. Whereas CRM, untreated and treated PA and RM sample, a crossover behavior were observed. An exact solution suggested for each model and the decay rate were obtained. Overall stimulations done shows is in good agreement, showing highest removal values for Mn lowest for Zn metal. It was then suggested that, the developed mathematical model was useful for describing the adsorption of the above metals, which could also help in designing the proper way that effluents can be discharge from abattoir industries.