ADSORPTION OF HEAVY METALS FROM WATER USING MORINGA OLIFERA PODS MODIFIED WITH IRON OXIDE NANOPARTICLES » STED Journal

class Akismet_REST_API { /** * Register the REST API routes. */ public static function init() { if ( ! function_exists( 'register_rest_route' ) ) { // The REST API wasn't integrated into core until 4.4, and we support 4.0+ (for now). return false; } register_rest_route( 'akismet/v1', '/key', array( array( 'methods' => WP_REST_Server::READABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'get_key' ), ), array( 'methods' => WP_REST_Server::EDITABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'set_key' ), 'args' => array( 'key' => array( 'required' => true, 'type' => 'string', 'sanitize_callback' => array( 'Akismet_REST_API', 'sanitize_key' ), 'description' => __( 'A 12-character Akismet API key. Available at akismet.com/get/', 'akismet' ), ), ), ), array( 'methods' => WP_REST_Server::DELETABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'delete_key' ), ) ) ); register_rest_route( 'akismet/v1', '/settings/', array( array( 'methods' => WP_REST_Server::READABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'get_settings' ), ), array( 'methods' => WP_REST_Server::EDITABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'set_boolean_settings' ), 'args' => array( 'akismet_strictness' => array( 'required' => false, 'type' => 'boolean', 'description' => __( 'If true, Akismet will automatically discard the worst spam automatically rather than putting it in the spam folder.', 'akismet' ), ), 'akismet_show_user_comments_approved' => array( 'required' => false, 'type' => 'boolean', 'description' => __( 'If true, show the number of approved comments beside each comment author in the comments list page.', 'akismet' ), ), ), ) ) ); register_rest_route( 'akismet/v1', '/stats', array( 'methods' => WP_REST_Server::READABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'get_stats' ), 'args' => array( 'interval' => array( 'required' => false, 'type' => 'string', 'sanitize_callback' => array( 'Akismet_REST_API', 'sanitize_interval' ), 'description' => __( 'The time period for which to retrieve stats. Options: 60-days, 6-months, all', 'akismet' ), 'default' => 'all', ), ), ) ); register_rest_route( 'akismet/v1', '/stats/(?P[\w+])', array( 'args' => array( 'interval' => array( 'description' => __( 'The time period for which to retrieve stats. Options: 60-days, 6-months, all', 'akismet' ), 'type' => 'string', ), ), array( 'methods' => WP_REST_Server::READABLE, 'permission_callback' => array( 'Akismet_REST_API', 'privileged_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'get_stats' ), ) ) ); register_rest_route( 'akismet/v1', '/alert', array( array( 'methods' => WP_REST_Server::READABLE, 'permission_callback' => array( 'Akismet_REST_API', 'remote_call_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'get_alert' ), 'args' => array( 'key' => array( 'required' => false, 'type' => 'string', 'sanitize_callback' => array( 'Akismet_REST_API', 'sanitize_key' ), 'description' => __( 'A 12-character Akismet API key. Available at akismet.com/get/', 'akismet' ), ), ), ), array( 'methods' => WP_REST_Server::EDITABLE, 'permission_callback' => array( 'Akismet_REST_API', 'remote_call_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'set_alert' ), 'args' => array( 'key' => array( 'required' => false, 'type' => 'string', 'sanitize_callback' => array( 'Akismet_REST_API', 'sanitize_key' ), 'description' => __( 'A 12-character Akismet API key. Available at akismet.com/get/', 'akismet' ), ), ), ), array( 'methods' => WP_REST_Server::DELETABLE, 'permission_callback' => array( 'Akismet_REST_API', 'remote_call_permission_callback' ), 'callback' => array( 'Akismet_REST_API', 'delete_alert' ), 'args' => array( 'key' => array( 'required' => false, 'type' => 'string', 'sanitize_callback' => array( 'Akismet_REST_API', 'sanitize_key' ), 'description' => __( 'A 12-character Akismet API key. Available at akismet.com/get/', 'akismet' ), ), ), ) ) ); } /** * Get the current Akismet API key. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function get_key( $request = null ) { return rest_ensure_response( Akismet::get_api_key() ); } /** * Set the API key, if possible. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function set_key( $request ) { if ( defined( 'WPCOM_API_KEY' ) ) { return rest_ensure_response( new WP_Error( 'hardcoded_key', __( 'This site\'s API key is hardcoded and cannot be changed via the API.', 'akismet' ), array( 'status'=> 409 ) ) ); } $new_api_key = $request->get_param( 'key' ); if ( ! self::key_is_valid( $new_api_key ) ) { return rest_ensure_response( new WP_Error( 'invalid_key', __( 'The value provided is not a valid and registered API key.', 'akismet' ), array( 'status' => 400 ) ) ); } update_option( 'wordpress_api_key', $new_api_key ); return self::get_key(); } /** * Unset the API key, if possible. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function delete_key( $request ) { if ( defined( 'WPCOM_API_KEY' ) ) { return rest_ensure_response( new WP_Error( 'hardcoded_key', __( 'This site\'s API key is hardcoded and cannot be deleted.', 'akismet' ), array( 'status'=> 409 ) ) ); } delete_option( 'wordpress_api_key' ); return rest_ensure_response( true ); } /** * Get the Akismet settings. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function get_settings( $request = null ) { return rest_ensure_response( array( 'akismet_strictness' => ( get_option( 'akismet_strictness', '1' ) === '1' ), 'akismet_show_user_comments_approved' => ( get_option( 'akismet_show_user_comments_approved', '1' ) === '1' ), ) ); } /** * Update the Akismet settings. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function set_boolean_settings( $request ) { foreach ( array( 'akismet_strictness', 'akismet_show_user_comments_approved', ) as $setting_key ) { $setting_value = $request->get_param( $setting_key ); if ( is_null( $setting_value ) ) { // This setting was not specified. continue; } // From 4.7+, WP core will ensure that these are always boolean // values because they are registered with 'type' => 'boolean', // but we need to do this ourselves for prior versions. $setting_value = Akismet_REST_API::parse_boolean( $setting_value ); update_option( $setting_key, $setting_value ? '1' : '0' ); } return self::get_settings(); } /** * Parse a numeric or string boolean value into a boolean. * * @param mixed $value The value to convert into a boolean. * @return bool The converted value. */ public static function parse_boolean( $value ) { switch ( $value ) { case true: case 'true': case '1': case 1: return true; case false: case 'false': case '0': case 0: return false; default: return (bool) $value; } } /** * Get the Akismet stats for a given time period. * * Possible `interval` values: * - all * - 60-days * - 6-months * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function get_stats( $request ) { $api_key = Akismet::get_api_key(); $interval = $request->get_param( 'interval' ); $stat_totals = array(); $response = Akismet::http_post( Akismet::build_query( array( 'blog' => get_option( 'home' ), 'key' => $api_key, 'from' => $interval ) ), 'get-stats' ); if ( ! empty( $response[1] ) ) { $stat_totals[$interval] = json_decode( $response[1] ); } return rest_ensure_response( $stat_totals ); } /** * Get the current alert code and message. Alert codes are used to notify the site owner * if there's a problem, like a connection issue between their site and the Akismet API, * invalid requests being sent, etc. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function get_alert( $request ) { return rest_ensure_response( array( 'code' => get_option( 'akismet_alert_code' ), 'message' => get_option( 'akismet_alert_msg' ), ) ); } /** * Update the current alert code and message by triggering a call to the Akismet server. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function set_alert( $request ) { delete_option( 'akismet_alert_code' ); delete_option( 'akismet_alert_msg' ); // Make a request so the most recent alert code and message are retrieved. Akismet::verify_key( Akismet::get_api_key() ); return self::get_alert( $request ); } /** * Clear the current alert code and message. * * @param WP_REST_Request $request * @return WP_Error|WP_REST_Response */ public static function delete_alert( $request ) { delete_option( 'akismet_alert_code' ); delete_option( 'akismet_alert_msg' ); return self::get_alert( $request ); } private static function key_is_valid( $key ) { $response = Akismet::http_post( Akismet::build_query( array( 'key' => $key, 'blog' => get_option( 'home' ) ) ), 'verify-key' ); if ( $response[1] == 'valid' ) { return true; } return false; } public static function privileged_permission_callback() { return current_user_can( 'manage_options' ); } /** * For calls that Akismet.com makes to the site to clear outdated alert codes, use the API key for authorization. */ public static function remote_call_permission_callback( $request ) { $local_key = Akismet::get_api_key(); return $local_key && ( strtolower( $request->get_param( 'key' ) ) === strtolower( $local_key ) ); } public static function sanitize_interval( $interval, $request, $param ) { $interval = trim( $interval ); $valid_intervals = array( '60-days', '6-months', 'all', ); if ( ! in_array( $interval, $valid_intervals ) ) { $interval = 'all'; } return $interval; } public static function sanitize_key( $key, $request, $param ) { return trim( $key ); } } ADSORPTION OF HEAVY METALS FROM WATER USING MORINGA OLIFERA PODS MODIFIED WITH IRON OXIDE NANOPARTICLES » STED Journal

Mokete John Phele^1,2, Fanyana Mtunzi^1,2, David Shooto²

¹Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Vanderbijlpark, 1911, South Africa, phelemj85@gmail.com

²Institute of Chemical and Biotechnology, Faculty of Applied and Computer Sciences, Vaal University of Technology Southern Gauteng Science and Technology Park, Sebokeng, 1983, South Africa

ORIGINAL SCIENTIFIC PAPER

ISSN 2637-2150
e-ISSN 2637-2614
UDC 504.43.054:669.018.674
DOI 10.7251/STEDZ2402039P
COBISS.RS-ID 141779713

Received: 22 October 2024.
Accepted: 23 November 2024.
Published: 29 November 2024.
http://stedj-univerzitetpim.com

Corresponding Author:
Mokete John Phele, Department of Chemistry, Faculty of Applied and Computer Sciences, Vaal University of Technology, Vanderbijlpark, 1911, South Africa, phelemj85@gmail.com

Copyright © 2024 Mokete John Phele, et al.; published by UNIVERSITY PIM. This work licensed under the Creative Commons Attribution-NonCommercial-NoDerivs 4.

Citation:
Phele, M., Mtunzi, F., & Shooto, D. (2024.). Adsorption of heavy metals from water using Moringa Oleifera pods modified with iron oxide nanoparticles. STED Journal, 6(2), 39-52.

ABSTRACT

The adsorption process by metal oxide nanoparticles has been investigated an effective agent for removing organic and inorganic contaminants from water and wastewater. In this study, iron oxide nanoparticles were synthesized in the presence of moringa oliefera pods as adsorbent for lead, copper and cadmium ions adsorption. Moringa oliefera pods biochar with Fe3O4 particles precipitated on the surface of biochar was synthetized by co-precipitation method. Batch adsorption method was used, and heavy metal ions percentage recovery was measured using ICP-OES. Effect of various parameters such as contact time, pH, metal concentration and adsorbent dosage was determined on the removal efficiency. The maximum adsorption capacities of Pb2+, Cd2+, and Cu2+ by MMC were 31.46 mg·g−1, 29.05 mg·g−1 and 27.66 mg·g−1, respectively. The Langmuir and Freundlich isotherm equations were used to analyze the equilibrium isotherm data. The adsorption process fit the second-order kinetics well in all cases, and the Langmuir isotherm equation fit the experimental data well.

Keywords: Moringa Oleifera, iron oxide nanoparticles, co-precipitation, adsorption